What is a Yeast Starter?
A yeast starter is a wort concoction that feeds healthy yeast and can double, triple or even quadruple your yeast population.
When to use a Yeast Starter
Usually Yeast Starters are recommended for beers that are high in gravity. Higher gravity beers have higher fermentable sugars and need more yeast. Now you could always throw in several packets of dry or liquid yeast but the cost of doing so will quickly prove to be too much. So the best alternative is yeast starters.
Of course, you can always use a Yeast Starter on any batch of beer you brew. After all happy yeast makes happy beer!
What happens if I don’t use a Yeast Starter?
You are essentially rolling the dice. Yeast starters prevent off flavors. If the yeast population is not high enough at pitching, fermentation will be slower and sometimes even incomplete! You risk diacetyl, phenol and esters building up and thus give your beer a pronounced chemical byproduct flavor. No one likes a wee heavy that tastes like Windex. Well maybe someone out there does, but they are weird and I do not associate with those kinds of people.
How to Make a Yeast Starter
What you will need:
Breathable Foam Stopper
Erlenmeyer Flask 2000ml (2 liters) – The Pyrex branded ones, not the knockoffs!
Stir Plate (optional but produces the maximum amount of yeast cells)
Stir Rod/Bar (plastic covered bars magnetic bars)
Light Dry Malt Extract (DME)
1x Packet of Yeast
Small Square of aluminum foil
If you are using a smack pack, go ahead and activate the yeast a few hours before you plan to make your starter. Measure out 1500ml (1.5 liters) of Water in your flask and add that to your pot. Mix in 1 cup DME. Bring your wort to a boil and boil for a few minutes. Make sure the DME is thoroughly dissolved into the water.
Now you need to cool the wort. Using a funnel, pour the hot DME into your flask, cover the opening with aluminum foil, and place the flask in your sink for a nice cold water bath. Remember in the list of equipment needed that I stated that you should have a Pyrex branded flask? If you use a cheap knockoff, you risk the glass shattering from thermal shock at this stage. When you have the wort cooled to pitching temperature, add your yeast to the cooled wort and seal opening with the foam stopper dipped in sanitizer solution.
Now comes the fun part. If you have a stir plate, this is where you are going to want to use it. Yeast cells need oxygen to multiply. So swirling the mixture is needed to make sure that oxygen is making it into the wort. If you are not using a stir plate, be prepared to start swirling… a lot. Every time to you walk by your starter, swirl it, watching TV? Swirl it, in the bathroom? Swir.. on second thought… you might want to wait until you are on your way back from the bathroom.
You get the point. You will be swirling a lot for the next 12-24 hours. Otherwise, place your starter on a stir plate, drop in the stir bar, set the speed, and walk away.
After incubation is complete, allow the yeast to settle to the bottom of the flask. If you started with a smack pack with 100 billion cells, you should now have somewhere around 300 billion cells! You have turned one pack of yeast into three, saving yourself close to $15! Now you have two options; Pitch it as is, or pour off some liquid and then pitch it. The choice is ultimately yours.
Sometimes you need even more cells, what then? Well the answer is simple. Pour off most of the liquid in the flask, Leave the yeast that you have in the flask, and add in more wort and repeat the process. You can repeat this process as many times as needed to achieve the desired amount of yeast your beer requires.
Pyrex Pyrex Pyrex
Before I wrap up this article I thought it important to show the differences between a “real” flask and a cheap knockoff so you can make an informed purchase. Besides the overall shape differences (specifically the neck) here’s what you should look for when purchasing.
Graduated to 1800ml with a total volume of 2L
Known for precise measurement
Known for withstanding extreme temperature changes
Perfectly flat bottoms (just like me, without the “flat” part)
Graduated to 2000ml with a total volume over 2L
No Pyrex Logo
Known for inaccurate measurements
Known for shattering from thermal shock
Not perfectly flat bottoms thus making stir bars go off center