It's another one of those topics I find bizarrely fascinating. Maybe because it's a very British tradition, at least when it comes to cask beer. The original purpose seems to have been to quickly bring into condition running beers, mostly Mild Ales. From there the practice spread to pretty much all cask beers. Though, admittedly, after WW I little other than running beers was brewed in Britain. At least in terms of draught beer.
If any brewers are reading this, I'd love to know if they prime their casks or not.
That's enough of my bollocks. Time for a nice juicy quote, fresh off the word grill:
"Beers consumed quickly may, however, be safely given a species of cask-fermentation, by adding to them some sort of fermentable sugar in solution. Such additions as these are termed priming, and it is customary to add them in the form of a syrup of about 1150 sp. gr., of which the Excise permit the employment at the rate of two quarts per barrel of beer. The sugars generally employed for this purpose, are invert sugar, glucose, and cane-sugar ; of these, invert-sugar is the favourite, as, in addition to ready-fermentability, it imparts during the early stages, a luscious sweetness which confers an apparent extra gravity on the beer. Glucose is also used, but more particularly in pale ales, where a dry flavour is more desired than the sweet fulness of invert-sugar. The very appreciable amount of unfermentable matter contained in glucoses, however, renders them less suited for priming purposes than arc invert-sugars. Cane-sugar is not often used as priming except in stout and porter brewing. The fermentation of the priming sugar throws no burden upon the secondary yeasts, since it is readily fermentable at the instance of the residuary primary yeasts ; it is at any rate a form of cask-fermentation which can always be relied upon, generally making its appearance within three or four days of the addition of the sugar. In the case of running mild ales the priming is added as a rule to the settling square; thus saving time and labour, and sufficiently answering the purpose for such beers as these, especially where the trade is a quick and uniform one. In the case of pale ales, or superior ales generally, it is best to add the priming to each individual cask just before it is sent out into the trade. By so doing, the customer gets the beer at its best, and with moderately quick draught the after-fermentation, due to the priming, will last out the required time. If in these cases the priming were added to the settling back, it would probably be all over by the time the beer was required in the trade. Priming solutions should always be boiled ; they should be made with the purest material, and made fresh at least once a week in winter, and every three days in summer.
Some brewers prefer rather to assist the yeast in degrading the maltodextrins into maltose, than to add extra fermentable sugar. To do this they add to the beer a small quantity of cold-water extract of malt, which, containing active diastase, will supplement the action of the secondary yeasts in degrading the maltodextrins. Only a small quantity needs to be used ; larger quantities would produce too rapid a removal of the maltodextrins, and this excessively early disappearance would be obviously dangerous in regard to the stability of the beer. Pale ales will stand one pint of concentrated extract per one hundred barrels of beer, added at racking; running ales double that amount.* The condition produced in this way is a steadier and more lasting condition than that produced by priming, and it is in most respects preferable to it. It depends, however, upon having a sufficiency of maltodcxtrin naturally present; priming, on the other hand, is independent of this. When the extract cannot be conveniently added to the beer in racking vessel, it may be added to the individual casks. In that case, it is previously diluted with beer to such an extent as to permit of the quantity due to each cask being sufficiently appreciable to be conveniently measured.
* Take two parts by weight ground pale malt, five parts by weight cold water; soak for six hours, stir periodically, then strain off and filter the solution through flannel. One pint of the solution to be used as above staled for too barrels of pale ale, and one quart to the same amount of running ale. The extract to be made fresh on each occasion. The grains are to be discarded."
"A text-book of the science of brewing" by Edward Ralph Moritz, George Harris Morris, 1891, pages 403 - 405.
Right, glucose, invert sugar and cane sugar are the favourite primings. With invert being the most popular and can sugar only being used for Porter and Stout. Not much very surprising there.
Chadwick recommended feeding the yeast after the first skimming with a combination of wheat flour and salt. For every four barrels of wort, two pounds of flour and half a pound of salt were mixed with a little wort and then added to the gyle-tun. The flour helped the fermentation and the salt clarification. It's worth noting that this preparation would have been illegal in a commercial brewery. (Source: "A Practical Treatise on Brewing" by William Chadwick, 1835, pages 48-49.)
If a fermentation were not vigourous enough and the yeast head discoloured, the solution was to "dress" the wort. The old method was to mix 1 lb of wheat flour and 4 ounces of salt per barrel into the wort and then rouse it thoroughly. When the problem was caused by too many unfermentable carbohydrates in the wort, this "dressing" could be effective. The diastase in the malt acted on the carbohydrates, making them more fermentable. The new method was to use just malt flour, without any salt. (Source: "Principles & Practice of Brewing" by Walter J. Sykes & Arthur R. Ling, 1907, pages 534-535.)
Barclay Perkins logs record priming particularly well. Once I've harvested the numbers I'll put together some lovely tables. Exciting times.
I gather that British brewers today tend to rack the beer to cask a few points above final gravity, rather than priming the casks. I'd like to know when this change happened.
ReplyDeleteI suppose it would make sense if it was about the same time as the use of chilled conditioning tanks.
A few points above final gravity... But how does the gravity descend then to final..?
ReplyDeleteWhy didn't the English just add krausen to the casks? Do you need to add more in relation to cask volume than will work to stimulate the secondary? But didn't the Irish do something similar with stout, the heading I think Faulkner called it?
Gary
Of the two breweries I've worked at one stopped the fermenation 2 degrees above final gravity and racked without finings and the other adds priming sugar (sucrose) to the casks.
ReplyDeleteOkay I see, there is enough residual yeast to get the racked beer down to FG.
ReplyDeleteI must say I've had a number of over-sweet cask ales this side of the pond, and now I can see why. Too much sugar is added, or it is not fermented out to the required point before draught dispense. There is nothing I dislike more than that heavy candy-sugar taste. A quart or two per barrel sounds like a lot to me. I really am opposed to additions of sugar to beer, at any level of the process.
Gary
Of the four breweries I've worked in two have done cask ale. I've tried a number of things because I like to experiment. Racking before terminal gravity, adding high krausen wort, priming with invert, honey and speise - each with good and not as good results. I tend to prefer beer that is fully attenuated and then priming the cask, usually with krausen.
ReplyDeleteI'm intrigued, but it seems a little risky for the brewer to introduce malt enzymes into the finished beer- it seems like the practice would add lacto and other bacteria from the grain as well, increasing the likelihood of spoilage. Maybe it would be inhibited enough by the hops, or maybe the beer would be drunk fast enough that it wouldn't matter?
ReplyDeletejwotis, it seems an odd idea to me. And a bit hit and miss. The predictability of sugar was one of its big atrractions.
ReplyDeleteBut using flour to restart fermentations often comes up in older texts.
Actually I've read that hops contain enzyme especially when fresh, and dry-hopping in part at least was to assist the secondary.
ReplyDeleteGary
"But using flour to restart fermentations often comes up in older texts"
ReplyDeleteBit of a myth though. According to Booth (I think), the dressing was to keep the witches out. That might not be as superstitious as it seems, although enough writers have laughed at it. It is probably a metaphor for keeping certain barley-loving flies out of the beer, like frit flies (not fruit flies). We have certain parallels in language today, but I cannot think of one at the moment.
However, on the rejuvenation front, the dressing gave a false impression. Often a languid fermentation may appear to occur but, for reasons that I do not pretend to understand, the CO2 decides to stay in solution rather than gas off to the atmosphere, meaning that the beer becomes supersaturated with CO2. Adding flour, and in particular the salt with its crystalline nature, provides nucleation zones and the excess CO2 instantly comes out of solution, gasses off, foaming like hell and bringing the yeast to surface with it. It is understandable that brewers may think that yeast likes such treatment, as a food.
It often happens in home brewing, inasmuch as occasionally the yeast does not appear to have taken off, so after a couple of days the home brewer decides to shove in an emergency packet of dried yeast. Suddenly the whole fermentation bin erupts, resulting in a mess that needs to be cleaned up and an argument with the wife if he has been foolish enough to ferment indoors.
Adding wheat and salt. What a bizarre practice. Seems hard to believe it wouldn't affect flavor in a bad way.
ReplyDelete@Gary, I doubt that any enzymes which might be present in hops affected conditioning if for no other reason than the availability of fresh hops would have been an extreme rarity before refrigeration. In any case, adding 'stale' wort would have probably introduced enough bacteria and yeast to condition the cask regardless of the sugar or yeast content of the finished beer.