The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Cold water and yeast

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Janet Yang's picture
Janet Yang

Cold water and yeast

"Dry yeast requires warm water (about 110°F.) to activate it by enabling it to absorb water and swell. Cold water will kill it."—Rose Levy Beranbaum, The Pie and Pastry Bible

Is this true? I would think that the yeast would simply slow down or go dormant. 

Janet

DavidEF's picture
DavidEF

I don't think the yeast could "slow down or go dormant" any more than it is when dry! But, it is certainly doubtful that it could be killed by cold water. I would think the yeast will awaken and become somewhat more active than it is when dry, but not nearly as active as it is in warmer climates, such as 110 degree water. I wonder where she got her information. If cold water kills yeast, I guess we shouldn't be keeping our precious starters in the fridge. And what about the ones who freeze a portion of their starter to preserve it for insurance against future starter emergencies? I think the evidence is stacked against Ms. Beranbaum's assertions!

suave's picture
suave

She is obviously referring to active dry yeast, in which case she is correct - I still think it's not so much "kill" as "really really hurt" but many references do say that ADY cells absolutely require warm water to reconstitute their walls.  Well, AFAIR.  Instant yeast is said to be sensitive to ice water, but I don't remember ever reading how much.

Mini Oven's picture
Mini Oven

is not very specific.  Nowadays, there are more types of dry yeast easily activated with water, anywhere from 40° to 75°F (Instant.)  Many books (and recipes) will give directions for the most difficult yeast to activate, the one coated with moisture resistance that needs melting.  That allows authors to save further explanation.  Too many folks are scared away from baking because of the yeast. Too much information too early can chase away a beginner, chase them away from their book.  So they tend to over simplify.   I think the point Ms Beranbaum is trying to make is that warmth is needed for successful rising.  (This can also be overdone.)  

One point, instructions like these should tell you that when you use instant yeast, you can use less because the protective coating is no longer there.  

Read the yeast packages in the store.  (I'm the one with a pocket magnifying glass taking my time.)  An education in itself.  If more than one type is available, compare.  It has been my experience that bulk packages are more economical but don't normally provide activation instruction (nothing to fret about.)  Most mfg. figure if you buy bulk, you know what you're doing.  The savings add up fast if you bake every week.  

The smaller pouches, those with two or three together in a strip often have their instructions scattered across three pouches.  This may save and enlarge type but once one portion is removed the directions are split up.  Sometimes the middle pouch looses identification.  One solution is leave the strip intact, do not separate the pouches and cut the top off each as needed.  Or before separating, dig out a permanent marker, make sure all pouches are labeled as to the exact type of yeast.  

 

Janet Yang's picture
Janet Yang

The yeast must be hyrdrated in water that is neither lackadaisical nor enthusiastic. Too cool and a dough-harming substance diffuses out of the yeast"—Arthur E. Grosser, The Cookbook Decoder (1981)

He appears to say that cold water is bad for the dough, not the yeast.

When this book first came out, I asked the author for more information on this "dough-harming substance," but he never answered my letter. After 32 years, I'm no longer expecting a response, but I'm still curious what the stuff is, if any of you know.

Janet

Mini Oven's picture
Mini Oven

for that one.   Any yeast experts?  The only thing my limited knowledge can think of is that the yeast might "spill their guts," hydrate and then dehydrate as they go dormant for survival.   Can they do that?  An interesting concept. 

mwilson's picture
mwilson

glutathione is released. So you are right about yeast spilling their guts, but there's no coming back from that. That yeast cell is dead. Glutathione can and is used as a dough relaxer making the dough slack / more extensible.

http://www.sfbi.com/images/pdfs/NewsF03.pdf

Re-hydration temp is important for Instant and active dry yeast.