The boil rate for homebrew can vary depending on the preferences of the brewer and the specific recipe being used. In the past, it was common for brewers to aim for a 10% to 15% evaporation rate over a 90-minute boil. This meant that around 10% to 15% of the total liquid volume would evaporate during the boiling process.
However, modern brewers tend to boil for a little over 1 hour, typically around 60 to 75 minutes. This shorter boiling time has led to a decrease in the evaporation rate. Nowadays, it is more usual to see an evaporation rate of around 6% to 8% of the total liquid volume.
The change in boiling time and evaporation rate can be attributed to several factors. Firstly, advances in brewing techniques and equipment have allowed for more efficient boiling and evaporation processes. Additionally, brewers have found that a slightly shorter boil can still achieve desirable results in terms of flavor and aroma extraction.
When determining the specific boil rate for a homebrew, it is important to consider the desired outcome of the beer. Some brewers may prefer a higher evaporation rate to achieve a more concentrated flavor profile, while others may opt for a lower evaporation rate to preserve delicate flavors or achieve a specific gravity for the beer.
To calculate the evaporation rate, brewers can measure the volume of the liquid before and after the boil. By comparing the two volumes, it is possible to determine the percentage of evaporation that has occurred. This information can then be used to adjust future brews and achieve consistent results.
It is worth noting that the boil rate can also be affected by factors such as altitude, ambient temperature, and the size and shape of the boiling vessel. These variables may require some experimentation and adjustments to find the optimal boil rate for a particular setup.
In my own experience as a homebrewer, I have found that a boil rate of around 6% to 8% works well for most of my recipes. This rate allows for sufficient evaporation to concentrate flavors without risking excessive loss of the liquid volume. However, I have also experimented with higher evaporation rates for certain styles of beer, such as Belgian strong ales, where a more concentrated flavor is desired.
The boil rate for homebrew can vary depending on personal preferences and the desired outcome of the beer. Modern brewers tend to aim for a slightly lower evaporation rate of around 6% to 8%, but this can be adjusted based on individual preferences and recipe requirements.