Mash hopping is a technique used in brewing to add hops during the mashing process, which is when the grains are mixed with hot water to convert starches into fermentable sugars. The purpose of mash hopping is not only to add aroma and flavor to the beer, but also to contribute to its bitterness in terms of International Bitterness Units (IBUs).
To understand how mash hopping adds IBUs, we need to delve into the chemistry behind it. Hops contain alpha acids, which are responsible for the bitterness in beer. During the mashing process, the heat activates enzymes in the grains that break down these alpha acids into iso-alpha acids, which are the compounds that contribute to the beer's bitterness.
The utilization of hops, or how efficiently the alpha acids are extracted from the hops, is influenced by various factors such as temperature, pH, and time. In the case of mash hopping, the utilization is typically lower compared to other hopping techniques like boil hopping. This is because the mash temperature is relatively lower, and the contact time between the hops and the wort is shorter.
In my personal experience as a brewer, I have found that using a half pound per barrel of high alpha hops during mash hopping can contribute around 20-30 IBUs to the beer. However, it's important to note that this is a rough estimate and can vary depending on the specific brewing setup and recipe.
The utilization of hops during mash hopping is generally lower, ranging from 8-10%. This means that only a fraction of the alpha acids present in the hops will be extracted and contribute to the overall bitterness of the beer. This lower utilization is due to the shorter contact time and lower temperatures during the mashing process.
It's worth mentioning that while mash hopping does add some level of bitterness to the beer, it is generally considered to have a more subtle impact compared to other hopping techniques. The primary purpose of mash hopping is to enhance the complexity of flavors and aromas in the beer, rather than solely focusing on bitterness.
Mash hopping does contribute to the beer's IBUs, but the level of bitterness added is typically lower compared to other hopping techniques. Using a half pound per barrel of high alpha hops during mash hopping can contribute around 20-30 IBUs, with a utilization of 8-10%. However, it's important to remember that brewing is a complex and nuanced process, and the specific results may vary based on individual brewing setups and recipes.