Saturday, June 20, 2009

How To Make A Yeast Starter

Besides fermenting ales at cool temperatures, I would rank pitching a large yeast colony near the top of my 'most important steps' list in brewing good beer.

Making a yeast starter is a pretty uncomplicated procedure with the great advantages of quick fermentation starts and the added benefit of good attenuation. The quicker you can get a dominant colony of your chosen yeast in the wort the better your odds of preventing unwanted wild yeast and bacteria from getting a foot hold in the environment. Here are the steps to amp up your yeast culture and get you the results you want.

  1. bring to a boil, 900 ml. of water on your stove top
  2. turn off the heat and add 1/2 cup of dry malt extract

  3. stir extract into solution

  4. turn the heat back on and boil solution for 15 minutes

  5. remove from heat, cover and cool to 70f. (I place the boil pot in a ice bath in the sink)

  6. aerate

  7. add yeast

The yeast colony will grow in the new sugar environment and is ready to pitch in about three days. You could also, step this culture up again growing the colony to an even greater population. To do this, repeat the process above and add to the yeast colony that you already started. First, pour off the excess liquid from the original starter, then add the fresh batch of boiled and cooled malt extract. The yeast will go through the same process as before, growing and consuming the new sugars. After several more days you will have an even larger yeast colony that will go to work quickly to ferment your next batch of beer. If you're not ready to pitch when the starter is complete then place it in the refrigerator until ready to use.

Some brewers will pitch the entire content of the starter but I usually decant the liquid off the top of the yeast leaving enough liquid to swirl the yeast into solution so that all of the yeast pours out easily.

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