Wort Grant

Placed between the lauter tun and the boil kettle, a grant offers brewers valuable information about runoff quality and serves as a handy buffer between grain and wort. The grant is rarely found in large commercial systems, but it was, at one time, a vital component of most German breweries.

The traditional purpose of a grant was threefold: (a) to avoid a potential vacuum in the lauter or mash/lauter tun during wort pumping for recirculation or filling the kettle, which could seal the mash to the false bottom, causing turbid wort or a stuck mash; (b) to allow the brewer to assess wort clarity and wort flow; and (c) in larger systems with multiple lauter tun outlets, to determine whether all parts of the grain bed flow sufficiently well or require raking or other measures to improve flow-through. The grant serves as a flow buffer.

The simplest grant design is essentially an open-top cylindrical can with wort flowing in from the bottom and being pumped off through a side port. This minimizes wort splashing and thus oxygen pickup.

In traditional breweries, however, especially in Germany and the Czech Republic, the grant is typically a long, shallow copper tub, bordered in regal brass, and fed golden streams of wort by a dozen or more swan-necked lauter run-off tubes. It is a strikingly beautiful design, part of a copper brewhouse that is sure to quicken the heart of any romantic brewer. Unfortunately, it is also a cause for worry, because traditional grants allow plenty of contact between wort and air, and modern brewing tends to eschew hot wort aeration, which can initiate staling reactions.

In the Czech Republic, wort oxidation from the run-off into traditional grants is partially responsible for the deeper gold colouring than is normally seen in German “pils” beers.

Modern brewing systems usually have no grant at all. Instead, they have special valves, often controlled by sensors and complex electronics, to allow wort to flow directly from the lauter tun to the kettle without the risk of a lauter tun vacuum or oxidation. The in-line sight glass used to check for wort clarity is sometimes called a “grant” but cannot offer the brewer the ability to really see the clarity of the wort.

Every PMG brewhouse is equipped with a high-quality stainless-steel wort grant (see photo below) for the brewer to be able to create the highest quality beer possible.