Just as with cask-conditioned beer today, all the care taken in brewing a good beer was in vain if it was poorly handled in the cellar.
The text below is taken from "A Treatise on the Brewing of Beer" by E. Hughes, Uxbridge, 1796, pages 34-37.
"Beware, lest you forget to pay attention to your beer which is at tap; for, "as the eye of the master maketh his horse fat", so the head of a family, now and then giving a look into his cellar, may be the cause of beer drinking more agreeable to his palate, by taking care that the vent-holes are kept closely stopped, and the cocks secure.
"Do not fail to stoop your cask when the beer is about two parts in three out; this should be done whilst the tap is spending, for then you will not disturb the sediment. By stooping the cask when the beer is about two parts in three out will prevent it from becoming flat and sour; when, on the other hand, it is too frequently to be observed when a person is drawing a pot of beer, the stream is impeded; for the beer, being so nearly out, will not run till it is stooped. Now before this, the cock discharging the beer but slowly, the air is admitted into the cask, which causes the beer to drink flat, and, perhaps, turn sour: therefore this will enforce the necessity of stooping your cask before it be so nearly out."
Stooping I take to be tipping up the cask. Which you need to do to get the last of the beer out of a cask. Interesting that the author recommends that this is done while the tap is open. That sounds rather counterintuitive.
"This is a fault with many publicans, not paying attention to their cellars; even many who brew their own beer are neglectful, notwithstanding their own interest and credit is concerned. Tis not uncommon for the vent-peg, and even the bung, to be left out of those casks which are actually on draught.
"Publicans, who retail common brewer's beer, and neglect their cellars, have this excuse, if their customers find fault with the beer, by saying "tis such beer as my brewer sends me," so it may be; but let a publican be served with beer of the first quality, it entirely depends on the management of the retailer thereof, whether the beer shall be of good or bad quality. This is proved by persons in the same town, each being served with beer from one and the same brew-house; there will be generally a disparity in the quality after it comes into the stock of the respective retailers thereof, which proves it to be the good or bad management in the cellar."
Just as today, there was plenty of room for the publican to fuck up a good beer, either through ignorance or laziness.
"I am convinced I shall not offend the attentive publican by what I have said respecting the cellar; but should this fall into the hands of the inattentive, it may offend; but that I will excuse, if, by the reading of this, he should be convinced of his error, and pay more attention to his cellar; that he may be enabled to draw a pot of beer to please those useful and valuable men, the labourer and the mechanic; and where they used to drink but one pot of beer with him, they may, from finding his ale much better than usual, perhaps, drink two."
There you have it: if the beer was well looked after, customers would drink more. I don't think I can argue with that.