Yeast Starter: How & Why we do them

Todays article is geared all about yeast starters. A yeast starter serves two main purposes.

The primary purpose would be to increase cell count. You have a single packet that has an estimated number of cells in the packet. Using a yeast starter by a mixture of dry malt extract and water you create a mini wort. In which you would add the single packet of yeast. This environment helps the yeast to multiply targeting around your ideal amount of cells needed for your batch size and gravity of your wort.

The second purpose is waking them up. Youre taking yeast out of the refrigerator in a dormant state. Then you are giving them an environment around fermentation temperature and a specific gravity ideal for reproducing. Allowing them to wake up from where they have been stored. Getting them active to go into your wort that youre brewing days later to create a healthy, strong, and active fermentation. When you are ready to learn more about the difference between lager and ales yeasts be sure to check our Ale vs. Lager – What’s the difference?

Two flasks of yeast starter solutions for brewing beer.
Credit: https://brulosophy.com/methods/yeast-starter-method/

Equipment for preparing a yeast starter

Things needed for yeast starter from the equipment:

  • Erlenmeyer flask, is made from a special kind of glass called borosilicate. It allows you to direct fire under it on the glass itself without it shattering. They may come in multiple sizes depending on what batch size you use. A 2-liter flask would be perfect if you do 5-gallon batches.
  • Dry Malt Extract
  • Stir plate and a magnetic stir bar

If you want to know how much dry malt extract and water you need for your specific yeast starter we personally use an application for that. It tells you exactly how many ounces or grams of dry malt extract with how much water to produce when you enter in what your expected volume and gravity of the wort you will be brewing.

Boiling the yeast starter and using protective gloves to shake the flask.
Credit: https://www.beveragefactory.com/blog/home-brewing/yeast-starter-video/

The process of making a yeast starter

For our specific starter, we need close to a pound of dry malt extract and about 4 liters of water. A lot of yeast cells are needed but the process is all the same. It’s just mixing drinking quality water which in our case we use reverse osmosis and the dry malt extract to your desired needs. When the burner is on and you just mix in the dry malt extract, the little clumps tend to settle at the bottom of the flask. Keeping it swirled and moving until the boil gets started is important.

Get some tin foil and set it on top to allow the steam to sanitize from the boil during this starter. Otherwise, you can just spray it with some sanitizer. It takes a while to get up to a boil. You can use a bigger flame. We tend to do it on a medium to medium-high heat just to avoid any scorching because once you pass this hot break it’s pretty easy going after that.

You only need a 10-minute timer to do these starters and the beginning is the most difficult. Be very careful in making a starter.

Swirling a flask of yeast starter
Credit: https://www.pinta.it/en/news/21-beer_yeast_/195-how_to_make_a_starter.html

Cooling it down

Fill your sink with cold water and put the starter in. Use ice to help to cool it down. Smaller starters don’t require that long long process. We cool it down to fermentation temperature. You can pitch the yeast around 70 to 75 F depending on the strain. Sanitize the scissors and the packets before you put the yeast in. Put it on the stir plate and wait. The best way is to wait 24 hours.

After put it in a fridge for another 24 hours and you will see the separation in the yeast. That is what you will pour off when you go pitch the starter. Cheers.

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