What ratio of liquid is lost during fermentation?

[EricTheRed]

Wondering where the water goes. Some obviously gets converted to co2. Some gets absorbed by the grain.

Eg.
23 kgs corn flour
10 kgs oatmeal flour
129 litres of water.
OG - 1.072 ish
FG - 0.990

Wort volume - 102 to 104 litres
Even if i squeeze i only get about 2 to 3 litres dirty liquid.

What ratio got consumed by what.
Where did the 20 to 25 litres go?

[Steve Broady]

Weigh that grain before and after, and I think you’ll find your answer. I am no chemist, but I don’t see how the water is being converted to CO2. I think it’s all staying right where you put it, but some is soaked up by the grain. No matter how hard I squeeze, my grain is still damp when I’m done. Think about how much water it would take to make that volume of grain damp all the way through.

[Laredo7mm]

I don’t know the actual amount of water that grains absorb, but I have always used 0.1 gallon per pound of grain.

You have 33kg of grain which is 72.93 pounds. 0.1 gallon per pound is 7.293 gallons absorbed by the grain. That 7.2 gallons is equal to 27.60 liters. 129 minus 27.6 is 101.4 liters. Looks like that is close to what you are getting.

I don’t ferment on the grain and I have never seen a loss of volume after fermenting my wort.

[EricTheRed]

I don’t know the actual amount of water that grains absorb, but I have always used 0.1 gallon per pound of grain.

You have 33kg of grain which is 72.93 pounds. 0.1 gallon per pound is 7.293 gallons absorbed by the grain. That 7.2 gallons is equal to 27.60 liters. 129 minus 27.6 is 101.4 liters. Looks like that is close to what you are getting.

I don’t ferment on the grain and I have never seen a loss of volume after fermenting my wort.

Thanks. Within tolerances then.

[Renhoekk]

Grains can easily absorb 1-2 times their weight in water, especially if you’re maxing the surface area by using flour.

The CO2 is produced from the yeast eating the sugar; water doesn’t turn into C02

[Setsumi]

I do 20kg maize meal in ~80lt water. After filtering and pressing fermenting on grain I end with about 65 to 68lt of beer. The scale tells the rest.