With most liquid yeasts, the use of a starter is necessary in order to create a viable amount of pitchable yeast. Even yeasts marketed as directly pitchable can benefit from the creation of a starter. A starter reduces "lag-time", before fermentation commences, and can help prevent a stuck fermentation. A typical starter involves fermenting a vial or package of liquid yeast in an small amount of wort a few days before brewing.
Dry yeasts do not require a starter. Making a starter with dry yeast can be detrimental to their performance because they can use their nutrient reserves before pitching.
Making a starter is relatively straightforward, far easier than brewing an entire batch of beer.
- Allow yeast to come to room temperature. If it is a smack pack, smack it first.
- Bring one pint of water to a boil in a two quart saucepan on the stovetop.
- Reduce the heat, add one half cup of Dry Malt Extract (DME) to the water, and mix it thoroughly.
- Gently boil the wort for ten minutes.
- Remove the saucepan from the stovetop, and cool it to room temperature, ~75ºF (~24ºC).
- Put the cool wort into an approximately half gallon (~2L) container.
- Cover and aerate thoroughly.
- Pour the contents of the yeast vial or smack pack into the container.
- Shake to mix the yeast into th wort.
- Cover the container with a piece of foil or a loose-fitting cap.
- There will be very little sign of activity, but the starter should be ready in one to three days.
- You may step up the starter by adding additional wort over a period of days.
- After you have brewed your full batch, you may either:
- Shake the entire mixture again and pitch it into the wort
- Chill the mixture a day before pitching
- Decant off the top layer of liquid before pitching just the yeast into the wort