Author Topic: Dry yeast re-hydration water calculation  (Read 879 times)

Offline Reifenberg

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Dry yeast re-hydration water calculation
« on: January 14, 2021, 03:07:21 PM »
On the starter tab, it appears the dry yeast re-hydration water calculation is using the recommended amount of dry yeast as the basis of the water calculation. Why doesn't it use what the user enters for the amount of yeast (for situations where one wants to underpitch)?

Offline BOB357

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Re: Dry yeast re-hydration water calculation
« Reply #1 on: January 14, 2021, 03:20:13 PM »
Probably best to use the yeast producer's recommendation. Different producers have different procedures for rehydrating.

Offline Kevin58

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Re: Dry yeast re-hydration water calculation
« Reply #2 on: January 15, 2021, 07:11:17 AM »
There is a split among homebrewers over whether it is necessary or beneficial to making a starter when using dry yeast. You really don't need to. Dry yeast packages can contain 20 billion cells per gram and with most packages being about 11 grams that is well over 200 billion cells. Plenty enough for your average beer.

In an article from 2019 published by Fermentis (Safale) they compared several methods of pitching dry yeast including rehydrating vs pitching directly into the wort. The method they found works best is add 1/3 of the wort in to you fermenter... sprinkle the dry yeast on top... and then adding the remaining 2/3 of your volume.

The article says using this method: "...eliminates the need for rehydration of the active dry yeast prior to the process."

PS. All that being said there are few hard and fast rules in homebrewing. If you rehydrate dry yeast or use it to make a starter and you like the results then by all means continue doing so.
« Last Edit: January 15, 2021, 07:24:47 AM by Kevin58 »
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