"The age at which ale is drank, will depend upon a private person's stock; the size of his cellar, &c. but more frequently upon his family habits, and the pecuniary means he chooses to devote to this beverage. Good mellow ale, soft and fine, may be had at a year old; and it is, perhaps, never better than from one year old to two. Some persons never reckon ale to be old, unless it drinks a little hard, or with some, approaches to sharpness, or acidity; but this is a false taste: old ale in this sense, it has been well said, is old ale spoiled.
After all, a hogshead or pipe of ale, that has. been properly brewed and carefully managed, will not always be fine when tapped. Suppose it be a year old, or what is more common, suppose it to be brewed in October (the best month in which to brew good ale for keeping), and tapped at the Christmas twelve-month following; if when tapped it be not fine, it may be corked up again, and stand another twelve-month, when it will probably be found not only fine, but greatly improved in flavour; but if it be wanted, it may be fined as follows: draw off a gallon or two, if the cask be a pipe, and take a quarter of a pound of isinglass, and some fresh hops, and scald them in a clean copper pan, dissolving the isinglass therewith; pour the quantity into a dry pail, and when cool put it into the barrel, and stir the whole together well with a long stick, or such an one as you have head-way to introduce; bung down the cask a few hours afterwards, and in a fortnight the ale will become fine. If the ale drink thin, and incline to be hard, let a pound or two, or more if required, of sugar-candy, bruised, be put into the pan with the hops, &c.
The method called marrying ale, we have often seen tried upon a private person's stock with success. It seems to increase its strength, but especially its mellowness and the fulness of its flavour, and consists in tapping a pipe or hogshead of ale in the middle, and when it is drawn as low as the tap, to fill up the cask with another brewing of wort. The particulars to be observed are: to begin upon a sound stock, such as is approved as to colour and flavour; for if there be any approach to acidity it will not do. The next point is to tun the newly-fermented wort upon the old stock, when it has fermented about twelve hours. The third particular, of great importance, seems to be, not to marry your ale in winter, but in autumn (October), for if your cellar be not a vault,the old stock is too chill, and the fermentation may suddenly stop: if this should happen, as in cellars that are not vaults, the heat may increase considerably in spring, the fermentation may be renewed, and the ale may spoil, or mischief happen to the cask by bursting. Ale that is brewed in the usual way will sometimes ferment in summer, and throw up the bungs of the barrels; especially if the fermentation have been hastily conducted, and little or no cleansing have taken place in the barrels after tunning (which is likely to be the case when brewing is performed in frosty weather); where this happens, the danger is that acidity will follow, and therefore the beer should be speedily used. When ale is married, the fermentation will bring away all the old hops, and it is not to be overlooked that the cork will rise that had been driven in with the tap. It is, therefore, requisite to work it out at the bunghole, skimming away the hops, &c. till they and the cork are discharged; then fill up the cask, and take out the top cork for cleansing, as before. It may be filled up several times with fresh wort, as in other cases, until the fermentation stops, and then the cork and bung put in (the latter very lightly) and left so until it is necessary to hop it down. The writer has refilled a cask in this manner five years successively, and had the ale always superior, and always alike in colour and flavour; in continuing this practice for a long period it is necessary to remove the casks for fear of accidents. The excellence of this ale is, that you can never guess at its age; it drinks always soft and mild, without any resemblance to ale recently brewed, and is equally remote from hardness or acidity"
"The London encyclopaedia Volume 1", 1829, pages 503 - 504.
