Trub is a byproduct that forms during the beer brewing process when wort (the liquid extracted from malted grains) is boiled with hops. As the wort reaches its boiling point, a variety of compounds are released from the hops, including alpha acids, beta acids, essential oils, and resins. These compounds provide bitterness, aroma, and flavor to the beer. However, they also contribute to the formation of trub.
The trub consists mainly of water-insoluble tannins and protein conglomerates, along with hop residue. Tannins are polyphenolic compounds found in plants, and in the case of beer, they come from both the malt and the hops. They contribute to the astringency and mouthfeel of the finished beer. Proteins, on the other hand, are derived from the malt and other adjuncts used in the brewing process. They play a crucial role in the formation and stability of the beer's foam, known as the head.
When the wort is boiled, the heat causes these tannins and proteins to denature and aggregate, forming solid particles. These particles combine with hop residue, such as hop cones or pellets, and settle at the bottom of the brewing vessel. This sediment is what we refer to as trub.
As a brewer, I've encountered trub numerous times during the brewing process. Its appearance can vary depending on the specific ingredients used and the brewing techniques employed. Sometimes, the trub can be quite dense and compact, while other times it may be looser and more dispersed. Regardless of its physical characteristics, trub is considered a waste product and is typically removed from the wort before fermentation begins.
To separate the trub from the clarified wort, brewers often transfer the hot wort to a separate vessel called a clarifying tank or whirlpool. In this tank, the wort is allowed to settle, and the trub settles to the bottom. The clarified wort is then carefully siphoned or pumped off, leaving the trub behind.
Once separated, the trub is discarded as it serves no purpose in the brewing process. However, it should be noted that some homebrewers and craft brewers experiment with reusing trub in certain styles of beer, believing that it can contribute to flavor and mouthfeel. Nevertheless, in commercial brewing, trub is typically considered a waste product and is discarded.
Trub consists mainly of water-insoluble tannins, protein conglomerates, and hop residue. These substances are formed during the boiling of wort with hops and settle as sediment at the bottom of the brewing vessel. While trub may have potential for experimentation in homebrewing, it is generally removed and discarded in commercial brewing.