The lauter grant is simultaneously one of the most useful and among the least publicized of the brew-day gadgets. 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. It is, in function if not always form, nothing more than an intermediate vessel in which liquid is collected on its way from the lauter tun to the boil kettle. The grant, thus, permits access to runoff as the mash is lautered and sparged. There are a few advantages to such a configuration:
- In systems that rely on pumps, the grant provides a buffer between the outflow from the lauter tun and the inflow to the boil kettle. This mitigates the potential for a vacuum, which might compact the grain bed and cause a stuck mash.
- The brewer may take wort samples from the grant with which to conveniently measure the pH of the runoff and avoid over-sparging.
- Similarly, a brewer can observe wort entering the grant and pump it back to the top of the mash until it has become sufficiently clear to be redirected to the boil kettle.
In a typical modern grant, wort enters a small cylindrical container through the bottom and is pumped away from somewhere nearer the top. Breweries in the late nineteenth and early twentieth centuries, however, featured elaborate grants that were fed by a long row of copper faucets, each of which drew wort from a different part of the lauter tun. Adjusting each faucet offered brewers precise control of the wort issuing from the tun. Such a grant can still be observed_ in situ_ at Anchor Brewing Company in San Francisco.
