from The Century Dictionary.
- noun In a brewery or vinegar-factory, a tank or vessel beneath the mash-tun into which the wort from the tun is discharged, and from which it is pumped into the copper to be boiled with hops.
from the GNU version of the Collaborative International Dictionary of English.
- noun (Brewing) A vessel which receives the wort as it flows from the mashing tub.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun brewing A
vesselthat receives the wortas it flows from the mashing tub.
Sorry, no etymologies found.
At the end of the three hours, let off the wort from the mash-tub into the underback-tub, which has been previously placed under the spigot and faucet ready to receive it; pouring the first that runs out back into the mash, until the wort runs free from grains, etc.; now put the hops into the underback-tub and let the wort run out upon them.
A Plain Cookery Book for the Working Classes Charles Elm�� Francatelli
There are also pipes for admitting "liquor" to the bottom of the tun, and for carrying the wort from the latter to the "underback" or "copper."
If it is not possible to arrange the plant so that the coppers are situated beneath the mash-tuns (as is the case in breweries arranged on the _gravitation system_), an intermediate collecting vessel (the underback) is interposed, and from this the wort is pumped into the copper.