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Fermentation/evaporation dough weight loss

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breadnik's picture
breadnik

Fermentation/evaporation dough weight loss

Dear fellow bakers,

This question has been bothering me for years but now it's actually becoming crucial. I am a small-scale commercial baker baking to order for local health food stores, and this morning I, once again, found myself half a loaf's worth of dough short -- that means, one of my customers got 1 loaf less than they ordered, which is embarassing for me.

I always weigh all my ingredients very, very carefully, and it is quite impossible that I would've undermeasured anything by so much that I'd end up 150 g. short on a 500 g. loaf (the last in a batch of 17 ). There were some descrepancies between pre- and post- fermentation dough weights in other batches, too, but not nearly as drastic as this one. I can only assume that this is due to water evaporation during the overnight fermentation. As far as I can tell this loss gets higher when the temperatures climb, and is barely noticable when it's cold. I suspect that air humidity also plays a role but I'm not sure.

My question is this: provided my assumptions are correct, is there any sort of formula that could help me figure out the ratio of this loss depending on the variables, so that I could accommodate for it by mixing, say, 5% extra dough?

Of course, there's a chance that such a formula would be too complex for me to solve, and if that is the case I can always mix extra 10% just in case. Just thought I'd see if there's some way to get a bit more precise about it so I don't have to waste my nice expensive organic ingredients.

Thank you so much in advance for any ideas.

Cheers,
Nika
aka Breadnik 

Nickisafoodie's picture
Nickisafoodie

Is the answer as easy as weighing the dough prior to the bake, and then after- with the difference being the amount to adjust for? 

I would think that loaf size matters and the nature of the underlying recipe/flour types/hydration.  So it would seem that a straight math formula that works for all may not be possible.

That said when I bake a 2.2 pound loaf at 68% hydration, 70% whole wheat and 30% white flour, my ending weight is about 92% of the starting weight.  After you determine your weight loss it would be easy to gross up the dough recipe.  And to be safe I would think that a flat 10% should accomodate all recipes/flour types if you didn't want to go thru this for each type of recipe you bake...

breadnik's picture
breadnik

Thank you Nick, you just helped me realize something I never really thought about. Of course, the highest hydration dough will have the highest weight loss %, there being more water to evaporate! Why didn't I think about it earlier?! And the bread I was talking about is my highest hydration dough (my Baked Potato-Rosemary, with 58% hydration+3.8% chopped raw scallions, baked as free-standing loaves). That explains why it is always the one to lose the most weight.

I am afraid I agree with your "a straight math formula that works for all may not be possible" -- it occurred to me after I posted this question that what I'm looking for might be a differential equation with variable hydration, dough weight, temperature, humidity and fermentation time. And I never was and still am not good at math, except baker's math. :)

So I guess I will have to figure out what margine of weight loss to assign to which bread and just go with it.

gary.turner's picture
gary.turner

Hi Nick,

I think Nika's problem is that she (?) weighs, mixes and ferments 1000g, and ends up with 900g of dough when dividing. Actually her numbers are 8500g of ingredients and 8350g of dough;  less than 2% loss.

@Nika: I presume you're going for a 1lb loaf after oven loss, which is probably about 10% of the dough weight. I can see no compelling reason to worry about how the dough weight is lost, rather boost the ingredients by 2%. Back of the envelope scratching suggest we're talking about an extra 6.25g flour and 3.75g water per loaf. (or proportioned to your particular hydration level)

cheers,

gary

breadnik's picture
breadnik

Gary,

Your guess is correct, I do measure 500 g. of dough to bake a 454 g. loaf. And thank you for taking the trouble to do the calculations for me. Nick said something that was really valuable to me or at least made me realize something important: the weight loss will be different for different types of bread depending on their hydration. THAT is the factor I never bothered to think about, which tells you exactly how scientific I am. ;)

So the 2% loss that you calculated applies only to this bread. Lower hydration doughs will have less of a loss, which agrees with my observations. So I just need to tell my Excel cheat sheet to multiply everything by 102 for mixing purposes but continue dividing the dough into 500g chunks.

Thank you so much,
Nika (and yes, I am female this time around;) 

Yerffej's picture
Yerffej

Hi Nika,

The chances for dough weight loss, as you describe, are high.  Certainly evaporation can and does take place.  If you are cold fermenting under refrigeration, that will take even more moisture.  I am a bit surprised to hear of you having this problem now as I would guess that it is quite warm/hot with high humidity.  In this weather I fight with dough gaining weight rather than losing it.  Dough gets lost in mixing, on bowls, tools, bench top and so on.  A little here and a little there.  Your loss against the total weight is very minor.

As previously suggested, it would be easiest for you to simply make a bit extra dough in your recipe and worry not about the little discrepancies.

Nice to hear from you again and I hope that all is going well for you,

Jeff


breadnik's picture
breadnik

Dear Jeff,

Sorry I disappeared for so long. See, I no longer live in Ohio, where, indeed, the humidity would be horrible these days. In the months that I've been missing we moved from NE Ohio to Northern Cali, I found a commercial kitchen, lined up my venues, obtained a license, started baking commercially, moved my kitchen closer to home (rather than driving 25 miles of crazy curvy mountain roads twice a day 6 times a week) and got relicensed AGAIN -- all of that in the last 8 months. So, you see, I've been busy and haven't had much time at the computer, except staring at my Excel reworking my formulas to adjust for total lack of humidity here. It's been and continues to be a lot of fun. A couple of really interesting projects happening, and I hope to write about them later.

I think what Nick and Gary said above just about solves my issue. I don't think I will be able to have a formula that I'm looking for but I do understand not where and why the weight loss happens, and I think I understand how to guesstimate the weight loss for a particular bread, so I will be able to make adjustments.

Good talking to you.

Cheers,
Nika

Just Loafin's picture
Just Loafin

Keeping an excel sheet with formulae so it's easy to adjust is of course good, but you should also be keeping a daily bake log. While it's work up front, it will help you understand what things might actually need tweaked in the excel sheets. There's no need to guestimate then. Over a period of two weeks or so, you should see a definite pattern and be able to assign average percentages to important things like weight loss for each recipe. You can then relax and just verify your baking log once a week or so, once you have good daily data. Always do a daily bake log for any new recipes.

- Keith

breadnik's picture
breadnik

Keith,

Thank you. That sounds like a great idea. What would I want to record in my baking log? Since I never thought about that, and never encountered any mentions of it, at this point I'd imagine it would be something like this:
1) Type of bread;
2) Batch size (with an actual gram amount of dough mixed, not just "18-loaves");
3) Ambient temperature;
4) Water temperature;
5) Time of mix;
6) Yeast % -- I ad lib this to a degree, depending on the ambient temperature, and it can go from 1% on very cold nights to 0.2% on hot summer nights. See, for reasons beyond my control I have very limited control of my environment, and, although I do have a walk-in cooler, I can't always use it to ferment my dough: I share my kitchen with a caterer, and sometimes he stuffs the walk-in so full I can't open the door without having boxes of strawberries or chicken breasts falling on me. ;) So I tend to think that the walk-in is not always available to me for overnight retardation.
7) Fermentation conditions (kitchen vs. walk-in)
8) Fermentation time (depending on the bake, I might be coming in to divide/shape/bake earlier or later).
9) Resulting weight loss.

What am I forgetting? I'm assuming that I'd only be recording things that are variable, mix- and fermentation-relatied, since my baking process is always [nearly] the same.

Chuck's picture
Chuck

Perhaps an alternative to figuring out how much loss there will be (2% is just "roundoff error" in my kitchen; I'm guessing it means a whole lot more to you:-) is preventing the loss from happening at all. You'd still deliver fair-weighted loaves to your customers, but you wouldn't have to pay for the bits of extra ingredients. Is there a way you can arrange to have enough humidity in your proofer to prevent the loss? In fact, have you got a way to put your whole proofer on a scale so you can see what's happening without even touching the dough?

(It wouldn't take much - typically when someone kludges up something with a baby humidifier or a steam cleaner, it's way way way too much and results in doughs so wet they have to be "wrung out". In fact, often nothing more than covering fairly tightly with plastic wrap during bulk rise and putting a big plastic bag over the whole rack when proofing is sufficient  ...but in a really dry semi-desert climate you may need a little more.)


Another possibility is to weigh the bulk and divide it by the number of loaves, figuring out how much each loaf should be to come out even. For example, in a particular batch you might find that each loaf of dough should weigh 490 grams rather than 500 grams. Measure the weight of the finished loaves, and make sure you're still delivering "fair-weighted" loaves to your customers. My guess is if the dough has lost more hydration while rising, it will then lose less weight in the oven, so the weight of a finished loaf comes out about right anyway.

breadnik's picture
breadnik

Dear Chuck,

2% is just "roundoff error" in my kitchen

Clearly, I'm much smaller than you :). At this point I'm just a one-woman show: I mix, I bake, I deliver, I stock my own shelves, I do my own accounting, my own purchashing, advertising etc. It's OK, I'm not trying to get huge, ever, and for now I'm just trying to grow very slowly and sustainably, without killing myself. Really, I am content with how things are progressing. That said, 2% wouldn't strain me much at all, as long as I'm planning on it. Very rough calculations show that it would cost me about $20/month [edited: per type of bread, there being 6-7 types of bread in any given month]. I think I can handle that to avoid embarassment. ;)

If I told what kind of equipment I'm working with you'd laugh: I have a 20-quart Precision Mixer, no proofer (let alone retarder/proofer), no steam-injection, just two Vulcan convection ovens, a very inconveniently-located warmer/holding cabinet, a speed rack and a walk-in cooler that I have a somewhat limited use of. I'd LOVE to have a better equipped kitchen, but I'm not there yet. I don't even own a scale that would go beyond ~8 kilos, including tare (and my mixing bowl is 2,913g!). If you have suggestions about a scale I'd be very happy: I need one badly! I'm sure it would cost a bit less than a 2-deck Bongard oven. :)

Soooooooo. All of this was to say that I really, really don't have much control over my environment the way you suggested, at least I don't think I do. What I CAN do, however, and thank you so much for that suggestion, is weigh the bulk, once I bought a scale of your (or anybody else's) suggestion, and then divide it by the number of loaves I need to make. That makes perfect sense as it WILL deliver fair-weighted loaves to my customers while not costing me much at all, other than a new scale.

Cheers,
Nika

 

suave's picture
suave

Likely it is not evaporation, but fermentation itself.  Yeast can consume a sizable percentage of sugars in your dough (I think 4-5% is quite typical),  converting them to equal amounts of alcohol and carbon dioxide.  The latter is then mostly lost when you work the dough.  So losing 2% is not at all surprising. 

breadnik's picture
breadnik

Aha! Good to know, thank you.