The Fresh Loaf

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Hamelman yeast percentage

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driechel's picture

Hamelman yeast percentage


 I have been using Jeffrey Hamelman's "Bread" for a few months now, but only now I found something that I dont understand.
I am a little bit confused about the percentages of instant dry yeast. Lets take the first recipe in the book, the baguettes with poolish, for example. He says you have to use 1.1 percent of yeast in total. I am using instant dry yeast, whereabout he says that you have to multiply the amount of yeast by .33.

Ok, so if I have 1000 grams of flower, then according to the formula I need 11 grams of yeast. But this is fresh yeast, so I still have to multiplie this amount by 0.33 now?? That means that I have 0.363 percent of instant dry yeast. Isnt that too few or did I use way too much yeast all the time??? My rising times were ok, slightly shorter always then what Hamelman says but not significant.

 Some one that has the book and feels like helping me out, please help me because I am really confused now.

bwraith's picture

Hi driechel,

Yes, I think he does mean to multiply the amount of fresh yeast by .33 to get the amount of instant dry yeast. There are a lot more organisms per unit of weight in instant dry yeast than in fresh yeast, about 3 times more, according to Hamelman's formula. From what I've read in various sources, that's a reasonable number.

The reason it doesn't make that much difference is that the instant yeast may take a little while longer than the fresh yeast to wake up, if you just mix it in with the dough, as opposed to proofing the fresh yeast before adding it to the dough, at least I think that may be what's going on. So, the instant yeast may have more organisms, but they take a little while to wake up, and therefore all told the time isn't that different.

Yeast grows exponentially for a period while it's multiplying inside the dough, like doubling every hour or so, let's say, depending on temperature and lots of other stuff. So, if you have triple the yeast, maybe it would reduce the rise time by an hour, but then if it takes a while to wake up, then that would lengthen it out.

I think the reality is that variations in temperature, nutrients in the flour, hydration of the dough, amount of salt, enzyme balance, and the effect of some of the additions to the dough like sugar, milk, fruits, spices, garlic, fats, and so on are probably big enough factors in how fast the yeast will multiply, that the importance of a factor of 2 or 3 in the number of yeast organisms you introduce to your dough may get lost in the shuffle and not be so noticeable. I've found that the amount of yeast you use is an amazingly forgiving variable, since you can usually adjust your fermentation times enough to keep the bread about the same.