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Pizza in particular is an interesting example because I would expect leavened bread products to be one of the cases where summing the components would cause mor

Pizza in particular is an interesting example because I would expect leavened bread products to be one of the cases where summing the components would cause more problems than usual (because you're going to lose sugar and other nutrients to the yeast). I'm not sure how many calories worth of carbs yeast consume during normal bread making, but I would expect it to be measurable. When making wine, yeast can easily consume pounds of sugar within days.

avar 10y ago
Couldn't things like yeast be handled by some standard pre-computed approximate lookups?
- alexbock 10y ago
  Definitely. You might not even have to consider baking time or temperature to get a good enough number to cover the calorie difference from lost carbohydrates and produced ethanol to meet the level of accuracy required for food labels. I only brought it up in the first place because whenever a simple solution to a complicated problem is put forward, it will inevitably turn out that it's either not general enough or special cases need to be handled to keep it simple. There's nothing wrong with needing special cases, but it's always nicer to figure out what the special cases will be before someone does a bunch of architectural work that hasn't considered them.
analog31 10y ago
I suspect it's not a large effect for bread. My family bakes our own bread, and I would say without having measured it on a scale, that there's not a noticeable loss of weight from one end of the process to the other. Also, you'd notice the stuff bubbling if there were a significant production of CO2. I've also made beer, and it bubbles like crazy once it gets working. One possible difference is that bread is made from (mostly) starch, whereas beermaking converts starches to sugars before fermentation, and the yeasts can work more efficiently on sugars. Of course you can also load up commercial pizza with sugar... one of the reasons why we make our own pizza.
- alexbock 10y ago
  If anyone can find a reference on the amount of CO2 produced during bread making it would be easy enough to calculate. I haven't been able to find any relevant sources except this old one [1] which mentions that the alcohol content in bread can be as high as 1.9 percent (which sounds quite high to me, but it's hard to critique when they don't explain their methodology). [1] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1709087/?page=1 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1709087/?page=1
  - analog31 10y ago
    Well, all I can offer is... tonight is baking night. I will weigh the ingredients, equipment, the risen dough, and the final product.
    - Symbiote 10y ago
      You could also seal the dough in a large bag, and measure the volume of gas produced.
      - eru 10y ago
        Won't the yeast get less oxygen that way?
    - mapt 10y ago
      How do you distinguish between evaporated water and respirated CO2? As an aside: My understanding was that most breads don't vent all that much CO2. Bread doughs are not risen in processes that leave the opportunity for rapid bubble formation and dissolution; If they did, baking after that first rise would give you a layer of thick dense bread, and another layer of fluffy bubble-bread on top.
    - analog31 10y ago
      So far... Flour 765 g, some white and some whole wheat Yeast 18 g, probably too much Water 611 g, eyeballed 600 ml in old glass measuring cup After kneading 1408 g After first rising 1416 g After "punch down" and second rising 1406 g Formed into loaves, waiting to rise before putting in oven Edit: After baking, 1271 g I'm using a creaky old Ohaus dual pan balance, surplus from an industrial lab. The process is not entirely "quantitative" in chemistry terms because there are some minor gains and losses. I have to flour the kneading cloth to prevent sticking, some dough may get lost on my bowl, and so forth.

avar 10y ago

Couldn't things like yeast be handled by some standard pre-computed approximate lookups?

alexbock 10y ago
Definitely. You might not even have to consider baking time or temperature to get a good enough number to cover the calorie difference from lost carbohydrates and produced ethanol to meet the level of accuracy required for food labels. I only brought it up in the first place because whenever a simple solution to a complicated problem is put forward, it will inevitably turn out that it's either not general enough or special cases need to be handled to keep it simple. There's nothing wrong with needing special cases, but it's always nicer to figure out what the special cases will be before someone does a bunch of architectural work that hasn't considered them.

analog31 10y ago

I suspect it's not a large effect for bread. My family bakes our own bread, and I would say without having measured it on a scale, that there's not a noticeable loss of weight from one end of the process to the other. Also, you'd notice the stuff bubbling if there were a significant production of CO2. I've also made beer, and it bubbles like crazy once it gets working. One possible difference is that bread is made from (mostly) starch, whereas beermaking converts starches to sugars before fermentation, and the yeasts can work more efficiently on sugars. Of course you can also load up commercial pizza with sugar... one of the reasons why we make our own pizza.

alexbock 10y ago
If anyone can find a reference on the amount of CO2 produced during bread making it would be easy enough to calculate. I haven't been able to find any relevant sources except this old one [1] which mentions that the alcohol content in bread can be as high as 1.9 percent (which sounds quite high to me, but it's hard to critique when they don't explain their methodology). [1] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1709087/?page=1 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1709087/?page=1
- analog31 10y ago
  Well, all I can offer is... tonight is baking night. I will weigh the ingredients, equipment, the risen dough, and the final product.
  - Symbiote 10y ago
    You could also seal the dough in a large bag, and measure the volume of gas produced.
    - eru 10y ago
      Won't the yeast get less oxygen that way?
  - mapt 10y ago
    How do you distinguish between evaporated water and respirated CO2? As an aside: My understanding was that most breads don't vent all that much CO2. Bread doughs are not risen in processes that leave the opportunity for rapid bubble formation and dissolution; If they did, baking after that first rise would give you a layer of thick dense bread, and another layer of fluffy bubble-bread on top.
  - analog31 10y ago
    So far... Flour 765 g, some white and some whole wheat Yeast 18 g, probably too much Water 611 g, eyeballed 600 ml in old glass measuring cup After kneading 1408 g After first rising 1416 g After "punch down" and second rising 1406 g Formed into loaves, waiting to rise before putting in oven Edit: After baking, 1271 g I'm using a creaky old Ohaus dual pan balance, surplus from an industrial lab. The process is not entirely "quantitative" in chemistry terms because there are some minor gains and losses. I have to flour the kneading cloth to prevent sticking, some dough may get lost on my bowl, and so forth.