There are various factors that contribute to the amount of water lost during the brewing process, specifically from the mash to the fermentor. One important factor to consider is grain absorption, which refers to the amount of water that the grains soak up during the mashing process.
On average, it is commonly recommended to account for about 0.125 gallons (or 1 pint) of water per pound of grain for absorption. This means that for every pound of grain used in the mash, approximately 0.125 gallons of water will be absorbed by the grains. However, it's worth noting that different sources may suggest slightly different values, with some reports stating absorption rates as high as 0.2 gallons per pound.
To put this into perspective, let's consider a hypothetical scenario. Imagine you have a recipe that calls for 10 pounds of grain. Based on the average absorption rate of 0.125 gallons per pound, you would need to account for approximately 1.25 gallons of water being absorbed by the grains during the mashing process (10 pounds x 0.125 gallons/pound = 1.25 gallons).
It's important to note that grain absorption is not the only factor affecting water loss during brewing. Other factors include evaporation during the boiling process, trub loss (sediment and hop material) during transfer, and equipment losses. These factors can vary depending on the brewing setup and techniques used.
Additionally, it's worth mentioning that personal brewing experiences can also play a role in determining the specific water-to-grain ratio. Some brewers may prefer a higher or lower ratio based on their desired results, equipment limitations, or recipe requirements. Experimentation and adjustments are often necessary to find the perfect balance for each individual brewing setup.
The general guideline for water loss during the brewing process from mash to fermentor is approximately 0.125 gallons (or 1 pint) per pound of grain for grain absorption. However, it's important to consider other factors such as evaporation and trub loss, and to adjust the water-to-grain ratio based on personal preferences and brewing setup.