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LIQUID YEAST = LIQUID GOLD
As you read about this great hobby, you sooner or later will hear about liquid yeast and yeast starters. There is nothing mysterious about these things. In fact the reason they are talked about so often is simply THEY WORK. Liquid yeast is exactly what the word suggests, they are yeast in a liquid form, not dried. So why buy and use yeast in this form.
The advantages of liquid yeasts are specific desirable flavours in your beer, more control on what flavours are produced, better attenuation of all malt brews and access to a wide range of different yeasts.
A starter is just a small amount of active fermenting beer that you pitch into your main fermenter. Using a starter makes sure that you have plenty of active yeast at the start of fermentation.
However, at around $15.00 for a vial or smack pack of liquid yeast, most brewers wonder if it really makes a difference. And the cost of one packet doesn’t make you want to go out and give it a try either. BUT, by using the methods described below, and other tricks like an easy storage technique and using starters you can make your purchase of a liquid yeast last for at least 18 brews stored in just 6 stubbies in the fridge. If your are really careful about your sanitation, you can get 36 brews out of one packet. Now that is a lot cheaper and worth the effort.
Whats wrong with dry yeast
The dry yeast as supplied with most kits is designed to work with 1.7 kg of hopped malt extract and 1 kg of sugar. It ferments out fully the sugar and some of the malt for flavours and body. If you try and brew with all malt replacing your kilo of sugar, the result is often a high final gravity and a not very successful brew, as the yeast cannot use all malt very well.
The answer is to either use a better dry yeast such as Safale or to move onto liquid yeasts.
Liquid yeast are by their nature able to ferment beers that are all malt. These are the same yeast that commercial breweries use, so you are getting the same results.
To
brew a particular style of beer requires the correct ingredients, the
right technique and the
correct yeast. Using a dry yeast does not give you the option of brewing
to a specific style
or type of beer. Changing to liquid yeast will allow you to change the
flavours produced
in your beer, or copy a particular type of beer.
Are you ready to use liquid yeast
Before moving onto liquid yeast iron out any brewing faults you have. Don’t think liquid yeast will solve your brewing problems. It will not. Do some regular kits. Learn what controlling the temperature does to your brews. Practice good sanitation techniques.
Get someone impartial who can accurately judge the flavours of beer to check your homebrew to make sure you are not picking up infections. Use good ingredients. Replace the kilo of sugar with a mixture of dextrose, maltodextron and malt. Your homebrew shop will have one kilo mixes ready made up.
A
complete description of yeast properties is beyond the scope of this article.
Yeast properties
include what temperature range it ferments at, the flavours produced,
whether malt
or hops are accentuated, the amount of attenuation or how well the yeast
consumes the
available sugars, the amount of flocculation or how well the yeast settles
to the bottom of
the fermenter and clears the beer and alcohol tolerance. Your brewshop
may have a leaflet
showing the different properties of yeasts from a yeast supplier. Some
of the yeast suppliers
have websites showing their yeasts and properties.
So you are ready to give it a try
Liquid yeast is alive. So how it is treated will determine how it performs. Check the store you buy it from. The yeast should be stored in a fridge. Do not buy yeast that isn’t looked after. Check the date it was packaged. Naturally fresher the better. When you purchase your liquid yeast take it straight home and put in the fridge. They will die if left in a hot car or exposed to high temperatures.
Now when you get it you will want to make a starter and have it ready for your fermenter.
First rule of starters, BE CLEAN. Sanitation is very very important when
making starters. Clean
and sterilize everything. Wash your hands well. Sanitize the packet or
test tube before
opening. Sanitize the scissors. Sanitize the lids, funnels, workbench,
bungs and necks
of bottles before opening. Minimize the time of exposure to air. Don’t
cough on the gear.
Try not to breath on the equipment. Sterilize the starter jars thoroughly.
Good sanitizing
includes washing until clean in neopink or dishwasher detergent, soaking
in bleach
solution then rinsing in boiled water. Or wash till clean, rinse and use
idophor or 70%
alcohol in a spray bottle. Sanitize around bungs, lids etc with alcohol
or idophor on a
wipe or in a spray bottle before starting.
Making a starter
Starters are a way of making sure that you are pitching lots of happy hungry yeasts into your wort. They are made by adding yeast to sterilized wort. Second rule; use wort of approximately 1.040 sg for starters. This works out to be 1g of dry malt extract (DME) per 10 ml of water. Don’t use sugar or dextrose, as this doesn’t supply any nutrients for the yeast.
To make a 1 litre of wort for a starter for a batch of beer you will need a bottle of about 2 litres volume, a bored bung to fit and an airlock. Dissolve 100 gm DME in 1 litre of water then boil with the lid on for 10 minutes. Dissolve the DME by stirring over heat. Do not stop stirring until the DME is dissolved or it will sink to the bottom and scorch adding burnt flavors to your beer. Watch out for boil overs. You will have to stay by the stove the whole time or you will end up with malt all over the stove. By keeping the lid on you are sterilizing the inside of the lid at the same time. Cool this to room temperature. Leave the lid on until it is cooled. Get your sanitized bung, bottle, airlock and funnel on the sanitized bench.
Wipe around the lid of the saucepan with sanitizing solution. Sanitize yeast container. Take off lid, pour solution into bottle, add yeast, put in bung with airlock, shake for 1 minute to add some oxygen and leave to ferment at about 20 deg C.
When adding yeast to a starter make sure both are close to the same temperature to avoid shocking the yeast. Put the starter solution and yeast sample on the bench to both warm to room temperature before mixing.
After
24 – 48 hours there will be lots of movement through the airlock and lots
of foam on the
surface. Pitch the starter into your freshly prepared wort, oxygenate
for a few minutes by
stirring a lot and fermentation will start off quickly and strongly. Oxygen
is important at the
start of fermentation.
Getting value for money with your liquid yeast
How to make the liquid yeast last for 18 brews.
You will need six empty stubbies. Follow the above instructions and make you litre starter. Add your yeast. Leave at 20 deg, wait 24-48 hours. Before you pitch your yeast, pour about 100ml in each sterile stubbie,cap, and put in fridge next to the condenser where it is nice and cold, close to 0 deg C in temperature. This puts the yeast to sleep.
When you are ready to brew, say two days before, make a 1 litre starter in your 2 litre bottle, and add one stubbie, wait 24-48 hours, pitch most into your brew (except 100ml) and put that back into a sanitized stubby. Each stubby can be used 3 times before the risk of infection starts to become a problem. So you can easily make a liquid yeast purchased last for 18 brews (3 times 6 stubbies). If you are very clean you can get 6 brews out of a stubbie. That’s 36 batches.
If the yeast is not stored at close to 0 degrees C it will still ferment very slowly and may explode your bottles, or more importantly actually die. If you get an increase in pressure you may have to bleed the bottles of excess pressure. Pull the bottles out of the fridge, sanitise the bottles around the lids, gently just prise up a few crimps on the lid with a bottle opener, just far enough to allow excess pressure to bleed out, run the capper back over them and put straight back in fridge. If this is not done when you go to use the starter it may spray out on the ceiling or froth onto the bench, or worst case explode.
Label
the stubbies, "Warning do not drink", the date, type
of yeast and how many times used.
How much starter to make
Third rule of starters, use 5% for ales, 10% for lagers. So for an 20 litre batch of ale make a starter of 1 litre. For a lager make a bigger starter, 2 litres. For high alcohol beer double again.
Fourth rule of starters, step up in increments of ten. If you are making a starter from a small sample step up a few times and each step is 10 times bigger than the last. Say you are brewing from a yeast sediment from a bottle fermented beer. Coopers is readily available in Australia. The yeast sediment is only about a teaspoon or two. Your first step would be to 20 ml volume, second 200 ml and third 2000ml (in bottles of 50 ml, 300ml and 3000ml.) Getting a culture from a bottle is very hit and miss. It depends on how the bottle is handled whether the yeast is alive or not. You will need 3 bottles that have airlocks and bungs fitted of volumes 50 ml, 300 ml and 3000ml. Pour the yeast slurry into the small jar with 20 ml of starter solution. If you see signs of movement, frothing and positive pressure in the airlock, the yeast is still alive and start stepping up.
Further Information
There is a lot of information available on the Internet, some of the better sites are :-
Using liquid yeasts really expands your brewing horizons. There are other
techniques including
water storage as listed at this website, taking a bottle of wort from
the fermenter
at high Krausen and saving in fridge till ready for next batch, saving
yeast cake from
the bottom of the fermenter and washing yeast. This method is only one
way of doing it, but
not the only way.
For your first liquid yeast I recommend you start with a clean fermenting yeast such as Whitelabs California Ale. This will not impart extra flavours in your brew.
Word of warning. Up till now you may have been using the supplied yeast with a kit. Handling starters and stepping up yeast starters gives more opportunities for infections the chance to grab a toehold. Once an infection has a toehold it quickly builds up as you step up and you can end up with every batch badly infected due to an infection when making your batch of starters. I recommend you perfect your brewing techniques on kits before starting with liquid yeasts. There is always a risk of infections when brewing.
Phillipa and Graham