What is a yeast starter? A yeast starter is essentially a mini batch of beer. It is made to give your yeast a hospitable environment suitable for them to reproduce making millions if not billions of yeast babies that will eventually help ferment your beer.
Benefits of Making a Yeast Starter
- A package of liquid yeast typically contains 100 billion yeast cells. A starter will allow the yeast to multiply so you can pitch the correct amount of yeast for your beer.
- Saves you money. You don't need to buy more than one package of yeast.
- As yeast ages, it becomes less viable. A yeast starter will bring it back up to strength.
- Helps speed up lag time. Your wort will start to ferment faster.
- Under pitching will stress yeast. This can cause phenolic and ester flavors in your beer. Prevent this by pitching the proper number of yeast cells.
- Erlenmeyer Flask (sized appropriatly for your starter size)
- Stir bar
- Calculation tool (Beer Smith, Mr. Malty, etc...)
- Light Dry Malt Extract (DME)
- Tin Foil
- Stir Plate (optional, but recommended)
- Sanitizer (Star San)
How to Make a Basic Yeast Starter
- Start the start the day before you brew. Try to allow 24 hours for the yeast to multiply.
- Use your calculation program of choice to determine the required amount of H2O and DME required.
- Mix the H2O and DME, then bring to a boil for 10 minutes.
- NOTE: As the work starts to boil it will foam up quickly. Remove from heat and stir to prevent a boilover. Return to heat and continue until the hot break passes.
- Sanitize your flask, stir bar and funnel.
- Place stir bar in the flask.
- Add the boiled mixture (wort) to the flask using the funnel.
- In an ice bath, chill the flask and wort to room temperature.
- Add the yeast to the flask.
- NOTE: Make sure you have done the previous step and chilled your wort first! If you pitch your yeast in boiling work you will KILL your yeast!
- Sanitize some tin foil and use it to loosly cover the flask.
- Place on the stir plate and allow to spin for 24 hours.
- Decant the foam off the top of the flask after 24 hours
- Allow flast to sit (at room temperature) without stirring for 2 hours.
- Yeast will settle out of suspension and you can pour the excess wort off. This liquid is not tasty. You don't want it in your beer!
Benefits of Stir Plates
- They are cool looking and make little home tornadoes.
- They increase O2 and decrease CO2. "Burp and Breathe"
- You increase cell count with increased oxygen.
- Yeast can be both anaerobic and aerobic
- When anaerobic (NOT in the presence of O2) fermentation occurs.
- When aerobic (IN the presence of O2) yeast reproduce like rabbits.
- The stir plate produces a perfect environment to allow your yeast to breathe and reproduce. This is also why tin foil is used, and not a rubber stopper. The flask must not be airtight.
- Yeast starters are a fast and easy way to increase your yeast cell count.
- Many brewers think this improves the fermentation process and overall outcome of their brews.
- Very few steps and supplies are required.
- Stir plates aid in the starter process by introducing plenty of O2 for maximum reproduction.