Home Distillation of Alcohol (Homemade Alcohol to Drink)
Fermenting
Summary
Ferment the mash/wash at a constant 25oC, using 1.5g/L of good yeast.
Use an airlock to let CO2 out but not let air in.
Let the yeast settle out, and possibly even filter the wash before
putting it into the still.
Fermentation is the conversion of sugar to ethanol and carbon dioxide by yeasts (wort to wash).
Theoretically 10 kg of sugar will produce 6.5 L (5.1 kg) of ethanol and 4.9 kg of carbon dioxide. In doing
so, some energy is released (about 2.6 MJ/kg of ethanol) too.
Yeasts are single-cell fungi organisms. The most important ones used for making
ethanol are members of the Saccharomyces genus, bred to uniform, rapid
fermentation and high ethanol yields, and be tollerant to wide ranges of temperature and pH levels, and
high ethanol concentrations. Yeasts are facultative organisms - which means that they
can live with or without oxygen. In a normal fermentation cycle they use oxygen at
the start, then continue to thrive once it has all been used up. It is only during
the anaerobic (without oxygen) period that they produce ethanol.
There are three phases to fermentation once the yeast has been added:
an initial lag phase, where little appears to be happening, but the yeast
is adjusting to its new environment, and begining to grow in size
after about 30 minutes, the yeast begins to reproduce rapidly and the number
of yeast cells increases exponentially (thus known as the exponential growth phase).
Carbon dioxide is released in large quantities, bubbling up through the liquor. As the
fermentation proceeds, the yeast cells tend to cluster together (flocculate).
The last phase is a stationary phase during which nutrients are becoming scarce,
and the growth rates slow down. The evolution of carbon dioxide slows down, and
the yeast settles to the bottom of the fermentor.
Yeast produces 33 times more alcohol while reproducing than when resting (so most of the gains are in the
first couple of days, then you're just relying on the large numbers of yeast finally present to slowly work their way
through the remaining sugars)
Once the nutrients have run out, and the fermentation has become "stuck" or sluggish, it is
then too late to provide either nutrients or new yeash. If this happens really early
during the fermentation, then you're in trouble.This is because when
a yeast is deprived of a nutrient, it grows as best as it can with what is
available, and then growth comes to a halt. Those cells are then put together
with less than satisfactory levels of (lets say) protein due to deficient
nitrogen. Their enzyme content is less than adequate, and they don't
metabolize well at all. Growing cells are ~33 x faster at ethanol production
than non-growing cells. Supplementation at that point does not reinitiate
growth in the older cells. By that time the medium is higher in alcohol and
still deficient in some nutrients. Some cells may even have died.
Even supplying the combination of BOTH nutrients
and new yeast won't get the activity restarted again.
So the trick is to ensure you have enough nutrients available at the start of the fermentation.
You end up with about 2g per litre of yeast (eg 40g in a 20L wash) This is why you don't get the full 51.1%
conversion of sugar to ethanol, and gives some idea of the amount of nutrients - particularly nitrogen - that
you need to supply.
Bakers yeast will produce a maximum of around 14% alcohol, whereas the "turbos" can
generate up to 20% alcohol. Obviously you'd use different amounts of sugar for either case.
Its not that the Turbo makes a higher % from less sugar, its advantage is that it can handle the higher
concentrations (first of heaps of sugar, then later, the high alcohol %), and hence you need proportionally less water.
Hence you end up with more alcohol in your 20L wash, because you are able to put more sugar in.
Only use the Turbo's if you're after a "neutral" alcohol. If you're trying to make a flavoured spirit,
(eg corn whisky, brandy, rum, etc) then use a yeast which will help give you the flavour profile
that you desire.
While making the ethanol, the yeasts will also make very small amounts of other organic compounds - including
other alcohols, aldehydes, esters, etc. These are known as the "cogeners" or the "fusel oils". It is the presence of these that
give the alcohol its flavour. So when trying to make a neutral spirit, we'd try to minimise their presence,
but if making a whisky, rum, brandy etc, then we need a very small proportion of them present.
Fusel oil concentration in the wash can be up to around 0.24 g per Litre from 20% sugar (eg about 3.2 mL from a 20L wash)
Fusels increase depending on ...
* yeast strain (eg Saccharomysce cerevisia makes more than S.carlsbergensis)
* temperature (higher temp = more fusels)
* increased aeration and agitation (news to me ! so don't over-stirr it !)
* wort composition (nitrogen sources and readily metabolised sugars)
The most common limiting factor for yeast growth is a lack of nitrogen. Nitrogen is approx 9% of the cell mass.
Most common form to add it is as the ammonium ion, as the sulphate and phosphate salts (phosphorus is
approx 1-2% of the cell mass, and sulfur 0.3-0.5% so these are needed too - this is a nice way of getting all three in there).
Add the ammonium phosphate at a rate of 25-50 gramms for a 25L wash.
The second most common limiting factor is a lack of oxygen, but it only needs it until high cell numbers are
present (eg during the first day) (so make sure that you've aerated the wash well just prior to adding the yeast,
but don't do this too much later in the game) "Splash filling" is enough to do the job.
Bacteria can double in number every 20-30 minutes, but yeast takes 3 hours (so guess which one will win
the race if an infection gets started and you don't deal to it. Another technique to help with this is to
use a lot of yeast - when using Bakers yeast, use at least 150g for a 20L wash.
Theres a fair bit of choice available as to which yeast to use. I'm personally inclined to use
the "Turbo" yeasts, which are pre-packaged with all the nutrients etc necessary. Thats because
I'm only ever doing sugar-water washes for pure neutral spirits, and I find it easy, convienient, and reliable.
I don't try and reuse it a second time, as I only distill every couple of months, and can't be bothered
storing it for that long. If however
you are doing more of a grain or fruit based mash, and interested in flavours, then consider some of the other yeasts.
Ted recommends
I have a yeast that can ferment to 17% with greater than 80%
attenuation in less than 4 days at 75 degrees F. It has a slight H2SO4
nose to it but it clears bright in 2 days and then you can't smell the
H2SO4. Esters and phenols are slight to none. No breadiness, sour or
vegemite aromas from the yeast that has been stored for 2 weeks and its
viability is 94% after 34 generations. This yeast is a work horse!
www.whitelabs.com/yeast_descriptions.htm#WLP001
- California Ale Yeast
This isn't the only one out there that is fantastic either.
Jack recommends ...
The yeast selection pretty much depends on what you are making -
For whiskey (corn or malt) the best bet is a dry ale yeast - Doric brnad ale is my
favorite (ask your homebrew shop owner what his most attenuative, alcohol
tolerant dry ale yeast is and use that).
For wine and mead the best choice is Lalvin's K1V-1116 - it has a 16% alcohol tolerance and is very fast (it
also has the ability to fight off bacterial contamination).
For plain sugar mashes (to be made into vodka) the best bet is Lalvin's EC-1118 - it has an
18% alcohol tolerance and is faster than the K1V-1116 - but it tends to result
in a stale, brackish flavor in the wine and the distillate - making it a bad
choice for a wine yeast (by overpitching this yeast - 100grams in 20 liters
and about 100 grams of yeast nutrient with 6-8 kilos of sugar you can make your
own Turbo- style yeast) - carbon polishing will take care of the stale taste
from this yeast- making it a good vodka yeast.
For making rum out of
molasses I like to use plain old bread yeast- it has a nice flavor when it's
distilled, and while it's fermenting the house smells like cookies.
NEVER use Montrachet yeast. I have had many recipes
for wine taste horrible becuase this yeast was what the recipe said to use-
it always ended up tasting (reeking) of sulfur- even when no sulfite was used
to make the wine. The sulfur smell it makes is more than capable of carrying
over into the distilled product (rotten egg schnaps was not what I was trying
for). If you find a recipe that uses this yeast- use the K1V-1116 instead.
I later found out that Montrachet was prone (genetically) to producing
hydrogen sulfide gas, hence the sulfur taste/smell whenever I used this
yeast. Avoid it at all costs.
Ken recommends ..."SAF-DISTIL.B-28" from D.C.L.Yeast
Nutrients
A slightly acidic environment is enjoyed by yeast, and also inhibits the development of
bacterial contaminants. The pH of the brew should be adjusted to between 4.0 and 4.5
prior to fermentation, using citric or lactic acids.
Nutrients also need to be present. Yeast cells require phosphorus, nitrogen and
potassium, as well as amino acids and vitamins, for metabolic processes. The extent
to how much is required depends on the feedstock being used. The nitrogen requirement
may be supplied in the form of amino acids, ammonia, or ammonium salts. If the
solids are separated from the sugar solution prior to fermentation (or say starting
only with sugar) the bulk of the protein will be removed, and hence a potential nitrogen
source lost. Ammonia or ammonium salts are the preferred source of of additional
nitrogen if its needed, however avoid using excessive amounts because it can kill the
yeast. Both nitrogen and phosphorus can be supplied by ammonium phosphate (commonly
available as a fertilizer). Many fermentations will proceed satisfactorly without
vitamin suppliments because the fermentation medium contains sufficient of these
nutrients, however in most cases, cell growth is enhanced when B-vitamins are added.
One recipe for nutrient ale salts is
58 g sodium chloride (common table salt)
170 g citric acid
7 g ammonium sulphate
6 g magnesium sulphate
2.5 g grape tannin
This mixture is hygroscopic (attracts water), so keep it in a cool dry place with a good lid.
The "Great New Zealand Home Wine Making Book" suggests to ...
"buy some ammonium sulphate or ammonium phosphate, and some
pottassium phosphate or potassium sulphate and add 2g (1/2 teaspoon)
of each to every 4.5 L. Another valuable addition is vitamin B1.
You can buy these as tiny 3 milligram tablets from your local
chemist or pharmacy and add one of these each 4.5 L" ...
Concerning the use of Urea in nutrients, Des writes :
According to 'The Food Regulations 1984, Amendment No. 5' dated 2nd
December 1991 regulation 235, General alcoholic drinks, subclause 3
says "General alcoholic drinks may contain any of the following:",
paragraph (i) "Yeast nutrients, except urea"
Which is what has been quoted in past correspondence and always
referred to when discussing the issue, however:
'The Food Regulations 1984, Amendment No. 9' dated 10th of October
1994 regulation 101, (3) states "Regulation 235 of the principal
regulations is hereby further amended by revoking paragraph (i) of
subclause (3)." ie the exception to urea above is now revoked.
On seeing this I contacted the New Zealand Health Department and
requested, under the Official Information Act, all the paper work as
to why the original banning and why the lifting of that ban.
Of course, I got screeds of paper but the story is that the ban was
instigated because of research done in England that pointed health
risks of urea as an ingredient for fermentation. Thus it was banned.
It was later realised that although these chemicals were present in
the fermented wash, they were not present once the wash had been
distilled. It appears that they are not carried over in the
distillation process, thus the ban for this type of alcoholic product
was lifted.
Also, don't use too much nutrient. It won't make the yeast work any faster, once
you've supplied its needs. What can happen instead is that the excess Ammonium disulphate can
react with (eg corrode) the copper in the condenser during distilling to produce ammonia and copper sulphate, which will turn
the alcohol blue, and smell of ammonia. If this happens, make sure you strip down your tower, and
clean it well. The blue alcohol can be cleaned up by adding some citric acid (50g per 5L)
(which will react with the ammonia to produce ammonium citrate which will precipitate
out along with the copper leaving hydrogen sulphyte and or sulphide), and then filtering it through
some coffee filters to collect the flocculant; the alcohol will then be ok to redistil.
Matt suggests
The White Labs site (http://www.whitelabs.com/brewery_servomyces.htm)
mentions that they are now distributing Servomyces
a nutrient which apparently even conforms with the Reinheitsgebot! It was
developed in Europe, and seems aimed more at the beer brewing market, but
it might still give interesting results for those doing a low-nutrient
wash ferment.
When the temperature of the wash has dropped below 26 °C, add the yeast.
Do not add the yeast too soon - if the temperature is above about 34 °C, it will kill the yeast.
You're aiming for around 10 million yeast cells per mL of wash.
A 25L wash at 1.080 will therefore need about 3 cups of slurry.
Get this amount by using the slurry left over from the previous run. See the comments below in the
Reusing Yeast section.
If using dried yeast, it can be helped along by letting it soak in about 1C of warm (24 °C)
water for about an hour beforehand. Use a high alcohol yeast such as for
champagne, or the new proprietary
alcohbase
or "turbo" yeasts which can generate up to 21% alcohol (who needs distillation ?).
If the pack you're using is one of those small ones, it will pay to grow it up to a
suitable size before using it (see Teds comments below).
Close the fermentor, and use an airlock. Keep the temperature around 28 C, and the specific gravity
should drop to approx 0.980 - 0.990 g/mL and have ceased bubbling within 5 days.
Jack H recommends ..
Try using cling wrap over the top of your fermenting vessel.
Secure with a rubber band(I cut mine from an old tyre inner tube)
Then prick about 6 holes in the wrap to allow the gas pressure to
escape.You can see when the fermentation is over and I have found
that I have never had a failure with this method as opposed to using
a fermentation lock .
If the fermenter doesn't bubble, check that the lid is sealing well. If you squeeze
the container when you put the lid & airlock on, the water should move up in the airlock,
then drop again when you let go. If it doesn't, then the lid isn't on correctly.
For excellent discussions about yeast, and how to get the best out of it, see the
Turbo yeast and
AllTech web pages.
Distillers' yeast is now sold in slurry form in the major homebrewer's
yeast banks. Unless you are making neutral spirits, do not use a
distiller's "fuel yeast". The Tennessee whisky yeast, Highland Scotish
yeast, Fruit Brandy/Eau de Vie yeast, ect. all add extra oganoliptics that
fuel yeast cannot.
Ryzopus derived Ryzozyme (Alltech Biotechnology) is a "cold mash" koji
(not aspergillis as used in Sake) now for sale from Alltech, Inc. Ryzozyme
step converts starch to sugar at room temp. I achieved a yield of 23.6%
alcohol (yes that's right) in 40 hours with 100% corn mash this fall at the
Alltech Alcohol School. (1 week for $950.00 US$). The entire Alltech
Biotechnology line is sold through Crosby & Baker
in the USA. Alltech,
Inc. products are sold world wide, so check the web. if your local
suppliers don't carry this yet. They also have great distillers yeast,
yeast nutrient and other biotech fermentation supplies. The brave new
worlds' bright side is here at last !
Temperature Control
Temperature control is very important during fermentation. Yeast is a living organism,
and will die if too stressed. Both alcohol and temperature stress it. With no alcohol around,
it won't die until about 40 °C. At 14% alcohol, it will die at 33 °C,
and at 25 °C if in 20% alcohol. So keep it below 25 °C at ALL times.
Lower temperatures will also result in less volitiles. When the temperature has been kept
below 30 °C the production of fusel oils is minimal, and is extremely small if
kept below a maximum of 25 °C. This is where you get into a bit of a trade-off;
if you keep it too cool, it will take heaps longer, with greater time for the risk of infection
etc to set in. At 25 °C, it will take 3 days to ferment 0.24 kg/L sugar, but at
15 °C it will take nearly 2 weeks.
An easy way to maintain the temperature in cooler climates is to wrap a
water bed heating pad around the fermentor, and tape the thermostat to the
side of it before
wrapping it all in a blanket. Other people just keep their fermenter in the hot water
cupboard. Another way is to keep it in a small cupboard or box with a light wattage
lightbulb to supply a lttle heat (but shield the bulb so that the beer doesn't
become light-struck). Some even use immersion heaters like those for tropical
aquariums - but these can be tricky to sterilise, you need to get the wires
through the lid in an airtight manner, and if you lift them out of the brew without
turning the power off, they can quickly overheat and burn-out (an expensive exercise
in forgetfullness).
If using the Turbo yeasts, pay particular attention to the temperature.
These babies can raise the temperature of the wash by 5-8 °C, so don't add
them until the wash has cooled to about 18-20 °C.
If you are fermenting large volumes,
you may need to actually cool the wash, either by dropping in frozen 2L softdrink bottles
of water, or getting fancy like big brewers, and running cooling water pipes through the
fermentor. The larger the amount you are trying to ferment, the harder it wil become
to control, yet it is critical that you try to keep it all at 25 °C plus/minus
only 1 °C. You may find washes larger than 200L difficult to control & keep cool.
Oxygen
During fermentation, yeast has a couple of choices. If it has oxygen available to it,
it will be able to reproduce quite rapidly (doubling every 3 hours). If there is
only limited oxygen available, it will turn its task to producing ethanol and other products
(about 1300 in all), like higher alcohols (sometimes called fusel oils), esters, organic acids,
and carbonyl compounds. To get good initial growth of the yeasts, you want to
have a bit of oxygen available - but you can do this simply by stirring the wash
vigorously when disolving the sugar. Once you have added the yeast, it is critical to seal the
container such that air cant get in, but you can still let the CO2 out, by using
an airlock. To minimise the amount of other volitiles produced, make sure that you are
using a yeast designed for the job, and keeping it happy with nutrients & with a stable temperature.
Fizz writes ..
..for those of us who have heard about the need for oxygenating the
water prior to pitching the yeast and (like me) cannot afford extra
equipment to do this I would recommend (if you have one) a kitchen
stick blender, like what you use to make soups or sauces etc.
2 minutes in that baby and the water had that much O2 in it, it
turned milky !
Stuck Ferments
If your fermentation peters out early in the story, it could be due
to a couple of reasons.
Nutrients. This will be the biggie. These are necessary if just using sugar/water.
If this is why its become "stuck", then there will be little chance of reviving it (sorry).
See the discussion above for more details.
I sometimes suspect that I haven't diligently rinsed
all the bleach from my fermenter, and that this has killed the yeast. Repitching
with more yeast gets it going again (and remember to rinse better next time).
Sometimes you haven't added enough yeast
(there almost is no such thing as "too much" yeast). Use a couple of packets if
you are using those little 5-7g sachets.
Temperature problems - too hot will kill the yeast, to cold will make it dormant.
Keep the temperature between 26-34 °C, and keep it constant - varying the temperature
will jepardise its run.
Do not add more sugar to a stuck ferment. It won't help.
You can still distill a wash which hasn't fully fermented out, but be prepared for some
fun. It is likely to foam up heaps, and possibly block the column if you don't give
it enough headspace, or use the "anti-foaming" silicon emulsions (wash conditioner) available in brewshops.
Also, because not all the sugar has fermented, you're likely to get less alcohol out, and
you may caramelise a bit of it on the element or the base of the pot (clean it well afterwards).
Another way of knowing how far the fermentation has progressed is to measure the
weight of your fermentor & contents. Half the sugar is expected to convert to CO2 gas and
bubble away. Theoretically the yield is 48.9%, but practically this is 40%
because some of the gas dissolves in the wort.
So if you have added 5 kg of sugar, and the weight has only dropped
by 1 kg, keep it going for a while longer (you expect 5 x 0.4 = 2kg weight loss).
Settling
Once fermentation has finished (eg final specific gravity of
0.990-0.980 reached), turn off the heat, and let the finished yeast settle over
a couple of days to the bottom of the container.
Siphon the clear wash into the still, and you're ready to go.
Be careful to not disturb the yeast layer, because if it gets into the still
it can result in bad smells and flavours. If in a hurry, you can use finings
(eg gelatin - 2g in 100mL to settle 25L) to
help settle/clear the yeast, or try placing the wash in the freezer, to chill
it fast & knock the yeast down. Passing the wash through a simple filter, or even
a couple of paper towels to clear out the remaining yeast will also help
improve the quality you later get. The simplest (& often most effective) technique
though is just time.
If you have to split the wash (say you've made more than the still can hold), just
pour the remaining wash into a container that will hold the
remains and be full. That is, ensure that the air in the container is
minimalised. By eliminating the air in your container you will lessen the
oxygen thereby lessening the chance of oxidation. This way you will be able
to do the remains in a second run any time. The wash should be quite safe for
weeks. Keep it sealed.
Alcohol Content of the Wash
You can easily calculate the strength of your wash, if you know your
starting & final specific gravities (SG) - measure these with a hydrometer.
The % alcohol is (Starting - Final) x 129. eg: if your sugar/water mix of
SG=1.120 drops to 0.980, then you have a wash with (1.120-0.980)x129=18.1%.
Reusing Yeast
It is possible to reuse the yeast several time. Ted Palmer advises :
You can "re-pitch" yeast more than 10 times in most cases, the biggest
factor in determining if the yeast is still healthy would be its
viability. Viability is the percentage of live cells in a given sample.
To test for this you will need a microscope, a hemocytometer and some
methylene blue stain. Here is a good link written by a friend of mine
that explains this method in detail
http://www.brewingtechniques.com/library/backissues/issue2.4/allen.html.
Another important factor is the genetic strength of the yeast, some
yeasts are very stable genetically others aren't. What this means is
that genetic mutations change the profile of the cells to the point that
they no longer resemble the parent strain. Some yeast strains mutate in
less than 4 generations where others are stable for hundreds. Turbo
yeast being a highly hybridized yeast falls into the former, I can't
tell you how well it will perform or for how many generations, you will
have to figure that one out on your own through experimentation.
Many packaged yeasts are mixtures of 2, 3 even 4 different yeasts, so if
one doesn't crop yeast at the right moment during a ferment one or more
of the strains could wind up missing in action. Also be aware that the
pitching rate or the number of cells added per ml is an important factor
in any ferment . The right # is 10 X 10^6 cells per ml up to 12 degree
Plato and you must add 1 x 10^6 per degree Plato above 12. That can be
allot of yeast in a high gravity wort. The caveat in yeast pitching is
more is better than less.
I've been doing some fermentation speed/alcohol-sugar tolerance
experiments. The Canadian wine yeast called Lalvin
EC-1118 (champagne-saccharomyces bayanus), when pitched at a massive rate (I
made up a starter of 10 lbs of sugar, 5 teaspoons of yeast nutrient, in 5 gal
of water, then when this was done fermenting, I repitched the thick yeast
cake at the bottom of the carboy into only 2.5 gallons of 15% potential
alcohol sugar water), with what seems like excessive yeast nutrients, it
acted the same as the Turbo yeasts I hear you guys in NZ talk about, plus,
with the competative factor (it's a "killer" yeast strain) no boiling or
campden tablets had to be used. Anyone who can't get a turbo yeast can make
one by "overpitching " this wine yeast! Fun experiment, but I tested every
wine yeast in the store, and I went through over 120 lbs of sugar. EC-1118
was the clear winner by a long shot. Hope this can help someone. (by the
way, fermentation took less than a week)
David Lamotte writes (to CraftBrewing@egroups.com (a brewing group for
Australians/Kiwis at eGroups)) ...
Now repitching is a great way to get huge amounts of yeast working for you
quickly, but you can also get the same amount of bugs doing nasty things.
Bacteria grow much more quickly than yeast, but are usually killed off as
the yeast get going making alcohol and lowering the pH (both are kryptonite
to bacteria). But the few that survive from the first brew quickly grow to
millions in the second and trillions in the third .... So it can often take
a few batches before you have to dump one down the drain.
You can just save some of the slurry from the bottom of the fermenter, but
it can only be repitched a few times as the 'gunk' builds up and coats the
yeast. The information that you were looking for comes from Wyeast's home
page (http://wyeastlab.com/hbrew/hbyewash.htm) and tells you how to wash
and store your slurry. You can replace the plain water with an Acid wash
which will kill any bacteria (but not wild yeast).
For yeast re-pitching & yeast washing applications the alcohol should
not go above 6%. This is so the yeast will not become stressed and start
to reproduce sexually (causing off flavors & mutations) rather than
asexually.
Please note that at the end of primary fermentation there is
enough yeast for four re-pitches. So, one can harvest 1/4 for re-pitch
unstressed yeast before stepping up with the remaining 3/4. Also if you
want to change your yeast strain by harvesting: Repitch of the bottom 1/3
will be more flocculent, repitch of the middle will be moderate 1/3 and
re-pitch of the top 1/3 will be hardley flocculent. It is suggested to take
1/3 top, 1/3 middle & 1/3 bottom to assure yeast character. What you want
the yeast to do now is up to you.
Jack divulges his method for preserving yeast cultures...
Most home brew shops sell syringes (about 10cc sizes) without needles- these can be used to
collect yeast in a perfectly clean manner. Fill up a measuring cup full of
hot water and microwave it until it's boiling, then stick the tip of the
syringe into the water and fill the syringe totally with boiling water, wait
one minute, then repeat twice more with boiling water. On the last draw-up
of the boiling water, instead of squirting it out, leave it in the syringe,
put the cap on and allow the syringe/water to cool in a draft free place.
When you brew your next batch of whatever, pour off all of the beer/wine/mash
until you just have the yeast layer covered with liquid (the yeast layer
sould never have been exposed to open air). Un cap the syringe and wipe down
the tip with alcohol, then stick it under the surface of the fermented liquid
near what looks like a healthy yeast colony, squirt out the water into the
general area to stir the yeast up a little bit (don't wash it away, just
unpack it from it's settled state- squirt the rest of the water away from the
yeast you are aiming for to prevent from scattering it to the wind-the amount
of water needed to blast the yeast loose depends on what kind of settling
properties it has)- then draw back the syringe plunger to collect the 10cc of
yeast slurry. The inside of the syringe has not been exposed to the
contaminating air, neither has the yeast (due to the protective blanket of
beer/wine/mash that you did not pour off), using standard beer "yeast
starter" techniques you can use the syringe to make ten "sub-cultures" (about
50 to 100ml), which can then be used to make a one litre starter for your
next batch- This technique will not work well for the Turbo yeasts designed
for nothing but sugar- but for expensive (liquid) yeast cultures for fancy
styles of beer/ wine/ whiskey mash- this system works wonders - I store my
syringes in the 'fridge- no acid washing no HEPA filter no extra food- they
last at least a month this way. Just make sure that if your mom house-sits
for you while your on holiday, that you show her what they are so she doesn't
think your a junkie and pours your trappist ale culture down the toilet. By
the way- special blends of various beer and bread yeasts work great for
fermenting whiskey mashes.
Sloppin' Back
Re-use of yeast is an old moonshiners trick also known as "sloppin' back".
This refers to adding the mash that was strained out of the wash just prior to
distilling, or the sludge left in the bottom of the fermentor, to the next batch of mash.
As Sam explains ..
I did't strain mine so to speak. I pumped out beer
from the barrel and left the grain. I used about half old and half
new grain. NO YEAST. It is already there. I added water and the same
amount of sugar as when I would start a fresh batch. Stir like crazy
and you only have to wait for 3 days max for the cap to form and fall
and you are ready for a good run. Like I mentioned, third time is the
best as far as taste and quantity in my opinion.
This can be a good source of infection for the next batch, but if it
goes well, it will help boost the yeast count heaps, act as a bit of a source
of nutrients (though its still best to add more of the real stuff like ammonia),
and should help buffer the pH a touch (dropping it a few 10 ths). The yeast that
you're reusing by this technique are those that have already shown themselves to
be quite happy in that type of mash, and are ready to go for the next lot.
It appears that the "Turbo" yeasts are only designed to be used once, and
not reused. Ola Norrman writes ...
Turbo Yeast (a mixture of yeast and nutrients) - shall
never be reused. There are 2 main reasons for this:
Yeast condition.
During the manufacture of dried yeast, very high
levels of phospholipids are accumulated within the
plasma membrane because the yeast is grown aerobically
(with oxygen). The yeast population which exists at
the end of fermentation has depleted levels making
yeast cells more sensitive during subsequent
fermentations and fermentation more likely to stick.
So the yeast produce and accumulates lipids during its
growth in the yeast factory. Then, during anaerobic
fermentation (without oxygen) in the wash, each new
generation of yeast contains less and less lipids.
Lipids are needed for alcohol tolerance which make
this important to 14% Turbos and far more important to
18% Turbos. If to many generations have passed
(because of reuse of yeast or to little yeast to start
with) the yeast have low "lipid protection" and
alcohol tolerance decrease.
Dried yeast also contains typically 15% Trehalose
which is a "protectant sugar". It gives the yeast cell
internal strength and also is an excellent "start
sugar" for the yeast to use at the start of
fermentation. Cells at the end of fermentation will
typically contain only 2 or 3% Trehalose. Trehalose
protect against the shock when the yeast are mixed in
the wash.
Nutrient depletion
Not relevant for beer, partly relevant for wine but
totally relevant for Turbo. So for Turbo, because the
sugar offers no nutritional value, re-using the yeast
a second time will result in a stuck.
Turbos also contains pH-buffer to give the yeast
perfect pH conditions. Nutrients not only work as
nutrients, they also keep the production of volatiles
down to a minimum. Nutrients are consumed by the
yeast. Re-use of a Good Turbo yeast will also result
in a lot more volatiles in the wash. pH-buffer will
not work in the second batch. There are other
ingredients making the CO2 leave faster, giving the
yeast cells something to claim to and move around in
the fermentation, assist clearing after fermentation
etc. Those functions will also be spoiled as they are
a part of the nutrients.
Nutrient composition are the manufacturers secrets.
One can not simply add some DAP
(diammoniumphosphate) or similar and expect it to work
the same. The first Turbo in the world was made in
Sweden. They are sold under the name Prestige and are
extremely good. At
http://www.turbo-yeast.com/intro.html
there is a lot of info about quality Turbos including
a "recipe" telling how "Bad Turbos" are made.
One could talk about genetic drift and bacterial risks
too, but it is not so important.
Freezing Yeast Cultures
Matt reports
Noonan's book does
mention freezing as a viable way of culture storage. It seems that yeast
cultures that have been refrigerated are allowed to warm up to around
50F/10C for about a week. This causes a sedimentation and the liquid
above the yeast layer is decanted off and the bottom layer is harvested.
This layer is squeezed of excess water and then tightly rolled into a
ball, stored in plastic wrap and then moved to a freezer. It apparently
can be stored for several months. To re-animate this yeast, it needs to
be thrown into a starter culture of aerated wort before pitching.
Mixing Different Yeasts
It is sometimes useful to use two different stains of
yeast at the same time; one strain for flavor and another for the
alcohol content.
Ray writes ..
It is quite a common practise to use a combination of yeast strains to acheive
the desired result e.g. I have seen a good general purpose type yeast which is
designed to go to around 13% mixed with a high alcohol yeast strain which is
designed to go to 18% or higher, the idea being that the general purpose yeast
does the majority of the work converting the sugar to alcohol then the high
alcohol yeast kicks in and takes the percentage up to the next level. I haven't
used that method for a long time but it seemed to work fine at the time.
Ted suggests ..
Use the low alcohol
tolerent yeast to ferment first to get as much of that yeasts "flavor " as
is possible. Then add more of the first strain to your ferment to push it
along a bit further. The reason for this is that most yeast can withstand
high levels of alcohol for a while before they go into stasis (they aren't
really dieing off). then go for the tolerent yeast. Be aware that in high
gravity ferments that the number of yeast cells must be increased a lot!!!
(High gravity is anything over 1.060) Most yeast producers won't tell you
this but, many strains are mixtures of yeasts that have different profiles
and variing flocculation habits.
On your recipe, you could try two seperate ferments one at a low gravity and
one high then combine for distillation.
The Omnipresent Mecakyrios does similar ..
I like the "Two Fermentations" idea. I brew my batches (a hard Cider and
Mead mix. Some call it a Melomel, but the taste is not like a Melomel at
all) then use the following fermentation method: primary fermenter for about
a month, rack into a secondary for about two months, rack into another
secondary for about a month or two (depending on how the brew is doing), and
if everything looks good I let it age for about a month and then distill it.
After I distil it, I let it age for about three to six months.
If I were to do the "Two Fermentations" idea, I could use the "flavor yeast"
in the primary, and the "strength yeast" in the first racking of the
secondary. Then I could shorten the first racking time and lengthen the
second to even things out.
Yeast
Heres some more postings from Ted Palmer about using yeast ..
Amount of Yeast
Many if not most
commercial distilleries use some form of brewers yeast. What should
determine the type and AMOUNT of yeast is the make-up of your wash. A common
problem isn't the type of yeast that you are using but rather how you are using
it. A 1.060sg wash will be reduced just fine by any yeast so long as there
are enough yeast cells per ml. and enough nitrogen to keep the cells
healthy. In fact by repitching more activly fermenting yeast several times
into a high gravity wash, a "beer yeast" can ferment up to 16 to 18 percent
alc. If you use a packet of dry yeast then there are too few cells let alone
heathy ones.
Here are a few guidelines for proper yeast use in any ferment:
You will need 10 X 10^6 cells per ml for any wash up to 1.050sg and 1 X 10^6
cells more for each 1.004sg above 1.050.
Always use a rigorously fermenting pitch of yeast, ie: never use yeast
straight from a package, always grow up enough cells for the SG you are
using (called a yeast starter). Say you are going to make 10 liters of wash
at 1.050, open the package and grow the cells in 10 ml. of 1.050 wash. When
fermentation passes the most rigorous point pitch the 10 ml. into 100 ml. of
1.050 wash, repeat this into 1 liter and then pitch into the 10 liters. with
higher gravities use 2 or more seperate yeast starters.
Yeast need proper nutrition, nitrogen must be present. If using only sugar
put 2 ml. of ammonia per 1 liter of wash. If using fruit juice or grain mash
0.5 ml. per liter. Yeast also need more than just sucrose for food, add some
fructose, dextrose, maltose or any other simple sugar. An acid isomerization
of sucrose(invert sugar) will also work if other sugars aren't available.
Reuse the yeast from the last batch you made! This is the easiest way to
make sure there are enough cells for your wash, keep any eye out for
infections though and only reuse yeast that fermented properly in the last
batch.
Aeration
In order to properly "grow up" a series of yeast starters you must aerate
the wash with sterile air or pressurized oxygen (O2). The reason for this
is that yeast cells bud or reproduce only when there is enough oxygen
present to grow. During fermentation yeast cells will still bud, but at a
slower rate since it has to pull oxygen out of chemicals. The amount of O2
required is small, on the order of 20 microliters per ml. to support the
budding phase.
So how do you put O2 in your wash?
Sterile air:
Pump air through a 0.02 micron filter and then a stone (fish tank bubblers
work well) into the wash. If you can't get a filter use a jar setup like a
thump barrel only put a stone on the inlet pipe, fill this with hydrogen
peroxide halfway full. pump air through this jar and then a stone into the
wash. Run this setup 20 - 30 seconds for each liter of wash.
Pressurized O2:
Use any tank of pure oxygen fitted to a stone on a length of tubing, run
for 5 - 10 seconds for each liter of wash.
Aerating a fermenting wash will result in one hell of a lot of yeast and
very little alcohol.
Aerating a fermenting wash for even a short time will oxidize flavor
components including ethanol!!!
Heres a couple of emails between Steve & Dr Clayton Cone
that are hugely informative ..
Below is the reply to my enquiry re turbo yeasts and stuck ferments. Dr. Clayton Cone is a microbiologist
and consultant at Lallemand which is the manufacturer of the Lallevin EC1118 yeast which is good for up to
18% alc/vol. He provides a protocol for the production of high alc wines/washes below. You may wish to put
the following links on your site, www.lallemand.com and
www.redstaryeast.com The latter has an interesting
text on the history of yeasts.
Regards, Steve
Steve,
I hope that you had a chance to read my articles in the Lalvin Home Wine
Making section of the Lallemand.com. I try to cover the role of yeast
rehydration, nutrients, oxygen, stirring, pH and other factors that are
involved in a healthy fermentation that should assure you of a complete
fermentation.
Most stuck fermentations today are caused by:
Mishandling at rehydration. Follow instructions very carefully.
Allow the temperature to rise too high.
No oxygen (aeration) during the first 36 - 48 hours.
No stirring or agitation during the first days of the fermentation and
near the end. The yeast settle out and are not up in the must where all the
sugar is.
Lack of yeast nutrients.
Too low pH
Toxic effect of Octanoic and decanoic fatty acids
I would first try to reactivate the yeast by adding Vi A Dry yeast residue
and stirring, allowing a little air to get into the must. Stir several times
for several days. If no activity is observed then you need to do one of the
following:
There will be no yeast growth with all of the alcohol present so you must
add a large number of live yeast to finish the job. Add 10lbs of properly
rehydrated EC 1118, K1 or L2226 directly to the stuck wine and aerate and
stir.
or
Calculate the right amount of EC 1118, K1 or L2226 required for the
total volume of stuck wine at 5lbs/1000 gallons. Rehydrate the yeast in 10
time its weight in 105F tap water. Add the dry yeast slowly to the water
while stirring to avoid lumping and allow to stand for a maximum of 30
minutes.
Add the rehydrated yeast to the following initial mixture which is 5% of the
total stuck wine volume:
2.5% of volume of stuck wine (25 gallons/1000 gallons)
2.5 % of volume as water (25 gals./1000 gal.)
2.0 lbs. Fermaid K & 2 lbs DAP /1000 gals. Of wine/water mix
Adjust sugar level of this mixture to 5% with juice concentrate or sugar (40
lbs sugar/100 gals)
Maintain temperature at 70 - 75F
When the sugar level has dropped by 1/2 (<2.5%), begin to add the stuck wine
to this starter. Add 2lbs Vi A Dry yeast residue/1000 gallons of stuck wine
before starting to add to the starter*. Add in batches of 20% of stuck wine
volume. When the sugar has again reduced half add the next batch. Continue
untill the fermentation has completed.
* This will adsorb the octonic and decanoic fatty acids that might be
present and also furnish nutrients for the yeast.
Here is a brief protocol for the production of high alcohol fermentations.
You can down size to your needs. EC 1118 is a good choice up to 16 - 18 %
alcohol. K1 and L2226 seem to work better at 18 - 20+% alcohol. The key to
the success of fermenting to these high levels of alcohol is management of
the yeast: lots of nutrients, pH control, small amount of aeration and
occasional stirring to keep the yeast in suspension.
Sprinkle the 6# K1 or L2226 yeast into 6 gallons of 105 F. water. While
gently stirring ,to prevent lumping. Allow to set for a maximum of 30
minutes. Stir to disperse.
To minimize cold temperature shock, cool the warm rehydrated yeast slowly ,
in stages, by adding equal volumes of juice to the slurry. The attemperating
stage is important to prevent the formation of unhealthy yeast cells (petite
mutants) which form when the yeast is suddenly exposed to greater than 20 F
drop.
Add the yeast inoculum to the bottom of the fermenter after a few gallons of
the juice has been pumped in. This allows the yeast added time to get
through its lag phase and exposes it to the necessary oxygen that it
requires for healthy , alcohol resistant cells after the growth phase.
Divide the nutrients into several portions and add in increments throughout
the first 72 - 96 hours.
Start the fermentation in juice that is below 24 brix, preferably 16-20
brix. The lower the initial brix the better the yeast will grow to achieve
the necessary population required to complete the last stage of the high
alcohol production.
Aerate or circulate gently for the first 24-48 hours. Do not put air cap on
for first 48 hours. Oxygen during the yeast growth phase is necessary to
produce the cell wall protection that is required towards the end of the
fermentation.
Monitor the pH carefully during the first 24 hours. Do not let it drop below
3.4. Adjust with potassium carbonate or other suitable alkaline material.
Monitor the fermentation closely. When the sugar drops to 4 brix, add
fermentable sugars to bring it back to 6 brix. Repeat this 4-6 brix. cycle
until you reach the desired alcohol level, allowing the last cycle to go to
completion (dry).
Comments:
The temperature should be 80 - 85F. for the first 48 hours and 70 - 80F.
for the remainder of the fermentation.
pH below 3.1 places an added stress on the yeast cell as the % alcohol
increases. It is best to maintain a 3.4+ pH. Use carbonates such as
potassium carbonate to keep the pH above 3.4. It is especially important to
monitor the pH during the early hours of fermentation when you are using
sugar, honey and some concentrates to increase the alcohol level. There is
little or no buffering capacity in these sources of sugar.
High levels of nutrients are absolutely essential for the yeast to produce
high levels alcohol.
100% fructose sugar is not recommended as a source of added fermentable
sugars. Most wine yeast ferment fructose at a slower rate and often times
have trouble fermenting to dryness.
You can expect 0.58 - 0.60 % alcohol by volume for each 1% sugar. Thus the
total brix or % sugar should be 33 -35.
With experience you may be able to adjust the brix between 4 and 10 rather
than 4 and 6 to minimize the number of sugar additions.
Every juice ferments differently You may have to increase the yeast and
nutrient levels or you may even be able to decrease one or more of them. If
you are using sugar, honey or concentrate to increase the alcohol level,
there are little to no nutrients present in these so you will have to add
all that the yeast need for a healthy fermentation. .
You should obtain a Clinitest Kit from your local drug store and use it
to monitor the sugar level near the end of the fermentation. It cost about
$0.10 per test. It is an ultra simple test normally used to test your urine
for sugar. 3 drops fermenting wine + 10 drops water in a test tube + 1
tablet, wait about thirty seconds. Read color compared to a chart.
One step, high gravity , 25-40 brix, fermentation:
High nutrient and yeast inoculum levels are necessary..
3-5X the above recommended yeast and nutrients are required.
Sugar is just as toxic to yeast as alcohol. Yeast growth decreases as
the brix increases. Above 25 brix the growth drops dramatically and has to
be compensated by increasing the inoculum. A general rule of thumb-1x10 6th
yeast cells / ml./degree brix; 1/2 # K-1 / degree brix/1000 gallons juice;
i.e., 1000 gallons of 30 brix juice would require 15# K-1 yeast.
There is usually very little suspended matter in the high gravity juice and
as a result the yeast tends to settle rapidly. The yeast on the bottom of
the fermenter participate very little in the sugar to alcohol process.
Therefore, stirring and or circulating constantly or frequently throughout
the fermentation is recommended.