The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

pre-bake weight to final weight calculation?

kimemerson's picture
kimemerson

pre-bake weight to final weight calculation?

Is there a simple way to calculate the final baked weight of a loaf? If I want to finish with, say, a 615 gram loaf, is there a way to calculate what the wet dough should be scaled at? I assume hydration% will be a factor. But without an abacus, slide rule and a degree in calculus, any simple rule-of-thumb trick?

Thanks

Abe's picture
Abe

As long as the recipe is the same... make one loaf and weigh it before and after baking. Note the percentage decrease. Then as long as you stick to the same recipe you'll know how much dough you'll need for the final dough weight.

kimemerson's picture
kimemerson

I wanted to be able to predict with a few different breads before having to bake them.  I would like to have some way to figure it out before baking so that if I want to alter the hydration % in a recipe I can have a clue as to what to expect. Or I want to be able to shoot for a desired finished weight without having go run any tests. If I have a desired finished weight I don't want to have to bake and bake till I get there. I want to know in the beginning. I have a 42" WFO and i bake about a dozen loaves at a time. So if I'm guessing things, it's over a lot of bread. I'd like to be right first.

Abe's picture
Abe

a bakers dozen is 13! Reason is because of weight loss. So every 12 they throw in an extra one for "free".

If we take this as a guide then the % loss is about 8.33%

Is that right? 1/12 x 100

David R's picture
David R

I suspect that the reason is more to encourage repeat business, and less to do with ratios and net weights.

gary.turner's picture
gary.turner

Over in Louisiana call it lagniappe, a little something extra.

g

OldLoaf's picture
OldLoaf

bake to bake and dough to dough.  My 65% hydration loaves tend to loose about  12-13% average, while my 75% hydration loaves average 15-16% loss.

I weigh my dough while I pre-shape, then again about 2-4 hours after the bake.  I typically only bake 2 loaves at a time though.  Other forum members may have different results...

Jeff

Edit: My 65% loaves are usually baked at 450F, and my 75% loaves at 500F. 

David R's picture
David R

Unfortunately, this question belongs in the "How long is a piece of string?" category. It's not possible to generalize - it even depends a little bit on what brand of oven you're using (because of different ventilation styles), among other things of course. Knowing that there will be some loss, and knowing to watch for it, are as good as it gets.

kimemerson's picture
kimemerson

So how do commercial bakers figure their weights for labeling purposes? If a loaf weighs 22 0z (616 grams) and says so on the package, they must have something figured out so it's consistent. They are required to be pretty accurate and they tend to have a variety of breads. So that they don't scale out, say 650 grams for every type of bread to get to 616 grams baked. It must vary and they must know. 

I plan to sell my breads retail and will need to put the weight on the label. I'd love some way to know. But it's fine for now to experiment. I have 5 different breads (plus baguette) and they are all just different enough that there likely won't be any single formula. Mine is a small operation and maybe I won't get arrested if I'm off a bit. 

David R's picture
David R

They test their recipe, and adjust. No one has ever complained (nor had the right to complain) about receiving a little extra for their money, so as long as the commercial baker makes sure they won't have a reasonable chance of going under weight, yet not waste much, it's good enough.

For that matter, you can plan your loaf weights before even settling on recipes. To increase or decrease the size of a recipe, you change the amount of flour first, and then proportionally (by weight) change everything else to match.

kimemerson's picture
kimemerson

Yeah, the missus and I were just saying that if I err in their favor I won't hear about it. But if I go under... 

I'll probably just bake a bunch and calculate averages, adjust as needed and cary on, before making labels. 

David R's picture
David R

People like sizes that are traditional, or if not traditional then a nice round number. But as long as you're selling good bread at a good price, they'll get used to it! 🙂

(One reason they like traditional sizes is to be able to do a direct price comparison between you and the competition.)

gary.turner's picture
gary.turner

But we make it up in volume.

Those commercial bakeries are talking thousands of loaves. As I recall from a tour many years ago, they test everything before each baking cycle. Not exactly economic for the small bakery. What you can do includes:

  • Post a minimum weight for each product. Run each loaf (quickly) across the scale and kick out the runts before packaging,
  • Use a printing scale and add the scale ticket to each loaf,
  • Do like McD does and sell by pre-cooked weight; already a part of the scale and divide process,
  • Or, you could sell by the loaf, if allowed in your jurisdiction.

Apropos of nothing at all, I figure for a 10% water loss, e.g. I weigh dough at 500g for a 1lb loaf, 750g for a 1½lb loaf and 1kg for a 2lb loaf. It's good enough for me, but probably not good enough for the bureaucrats.

gary

calneto's picture
calneto

I guess the way to answer this question is to run a few experiments. I have computed the loss for some of my loaves. They are hydrated usually at 70-75%. The loss has been in the range 18-20%. But I have only done this 6 times. If you are interested, you should keep record of the water content of the loaf and the total weight loss. With that at hand, you can find a line of best fit, assuming that weight loss is an affine function of the water content (in %).

David R's picture
David R

The truth is that for my personal order you will never run into trouble, unless you've made an obvious mistake like putting a half-size loaf into a full-size bag. (Even then, I just come back and quietly say "I think you gave me the wrong item".) And I suspect that the vast majority of people are like me, in not weighing every loaf of bread they bring home. Trouble really comes from three sources: the obsessed complainer who does weigh every loaf of bread they buy, the systemic repeated unintentional error that eventually gets spotted by ordinary customers, and the rare intentional crook. You're obviously not a crook, so the only one of the three you can prevent is the systemic repeated unintentional error. And you do that by being smart and staying aware of what you're selling.

kimemerson's picture
kimemerson

I have a NY State Ag/Mkt license and labeling is required for retail sales. And they are quite specific about what goes on the label, its size and its location.  I just pretty want/need to be accurate on the wildly odd chance that anyone from the State has a look. I'm more than happy to be just close enough, though consistent, in my weights. And I seriously doubt any buyer will ever take he time to weigh my breads. If not for the license and its requirements I wouldn't even be discussing weights. 

Just trying to stay a step ahead of the law.

Fernhorn Farm's picture
Fernhorn Farm

I have found dough calculators for final weight after doing multiple bakes to get a specific weight and calculating the difference. I have to say the latter was more specific. I too have a state Ag license and the labeling is quite specific. Have you ever weighed other bakery loaves? They are generally a little over in weight and I've never found one under. My customers like my bread and never have complained of the size of loaf or weight.

kimemerson's picture
kimemerson

I've never weighed other bakery loaves mostly because I don't buy them. 

And I do agree that I can get away with over weight bread (more than the label states); certainly no one would bring it to my attention as a complaint.

So I guess I'll simply do my baking, weigh the loaves to get an idea and an average, and keep at it to find the consistency, and do so with all my breads until I get a good and reasonably predictable system. As long as I find good averages on a regular basis I will be able to predict with some degree of accuracy what a pre-baked loaf will yield post-bake. I think.

 

David R's picture
David R

The same recipe in the same kind of pan in the same oven, is certainly going to be close enough not to worry. And I think the point from Fernhorn Farm, that your goal is "no underweight loaf ever", is a good one. The cost of an extra pound of flour "for the angels" is cheap - the cost of a lawsuit not so cheap.

Popular loaf sizes probably depend where you are and what type of bread you're making - but again, if it sells well and isn't breaking any laws then such technicalities don't matter. Supermarket bread here is 1 lb (454 g) for a regular loaf and 20 oz (570 g) for a big loaf, but that's here and that's supermarket bread. Any size that's somehow "intuitively reasonable" - basically, anything traditional (a pound, two pounds, twenty ounces) or anything that's a nice neat number or a neat fraction of it (a kilogram, 750 g, 500 g...) will immediately make sense to people. Advertising a 523 g loaf isn't wrong, but it takes more creativity. 🙂

bottleny's picture
bottleny

The average water loss for 15-17% by weight for open pan bake of standard wheat bread and 10-12% for close pan bake (source).

Here is another paper, "Effect of Baking Absorption on Bread Yield, Crumb Moisture, and Crumb Water Activity" (1992), giving similar figures.

(PS: I found these through Googling ;) )

As I recall, a member here once did similar experiment on water loss before and after baking but didn't find the source from search at first. Again, the amount of water loss really depends on the way you bake and the type of the bread (enriched or not).