"Naturally Conditioned Beers
These are beers which are not filtered nor artificially carbonated, but are bottled with a certain proportion of yeast. The yeast gives a slow fermentation similar to the final conditioning of draught beers in cask, and this slow fermentation gives the carbon dioxide requisite for satisfactory condition. The yeast slowly settles down, leaving the beer bright. Careful storage and handling after bottling is necessary, and the beer has to be poured out carefully to avoid disturbing the sediment. The result is a character and fullness which is not produced by carbonated and filtered beers. The beers require much more care and attention and a longer maturation period than filtered bottled beers and few breweries now brew their own naturally conditioned beer, but take delivery of a few well known national brands of pale ale and stout. As delivered to the bottling store they are usually in cask (generally hogsheads); and after a few weeks further maturation in cask they are either bottled direct from cask or more usually, the contents of the casks bulked in a tank (say of about 20 barrels capacity) and bottled from there. This latter procedure gives more uniformity of beer for bottling and enables the use of modern-type fillers. A well known brand of stout is now, however, delivered in bulk in tank wagons; being pumped to a storage tank and bottled from there without any further maturation, this having been completed at the brewery before delivery."
"Brewing Theory and Practice" by E.J. Jeffery, 1956, pages 365 - 366.
Now isn't that fascinating. Even though most breweries no longer brewed their own naturally conditioned bottled beer, they did package beer from other in this way. "a few well known national brands of pale ale and stout": he means Worthington White Shield, Bass Red Triangle and Guinness Extra Stout. At the time, these beers were very widely available and were to be found in the tied houses of other brewers. Guinness never bothered with tied houses and Bass only belatedly bought up pubs. For many years it depended almost exclusively on the free trade.
Shipping the beer in hogsheads seems quite old-fashioned. The famous Stout delivered in tankers in undoubtedly Guinness. Interesting that it didn't need to be matured by the bottler. Why is explained later.
"The exact storage and maturation of these beers before they are sent out is very carefully controlled by the brewery and the local breweries or bottling stores have only to ensure that the beer is given the correct final treatment. Nevertheless the earlier treatment of such beers is of interest to all brewers even if they may not have to deal with it themselves. When this book was first published in 1936 naturally conditioned beers probably represented the greater part of the bottled beer output of the average brewery. To-day the position has been reversed. The sections dealing with naturally conditioned beers are still valid, although of more limited application. Gravities and hop rates are lower on the average than at that time and as a result the long storage and maturation periods then given would be rather shortened to-day. These sections are given here with only minor alterations."
"Brewing Theory and Practice" by E.J. Jeffery, 1956, page 366.
I'm not so sure about most beer being bottle-conditioned in the 1930's. The move to filtered and artificially carbonated beers started in the 19th century. And many of the popular types of bottles beer in the 1930s - Brown Ale and Light Ale, for example - weren't very high gravity and wouldn't have been very suitable for this treatment.
"Naturally conditioned bottled beers are more restricted in their variety than are carbonated and filtered beers. This process is usually only given to pale ales, stouts and strong or old ales. It would be useless to attempt to produce a light gravity beer by this process, as it would be difficult to give sufficiently long maturation periods to give the necessary bottle condition, and the keeping qualities would be poor. In fact, even if practicable, it is doubtful whether such beers could produce the extra character and fullness to warrant the extra labour involved. The comments already given concerning quality of malt, water treatment and careful brewing apply very forcefully to such beers. While it is not true that fine filtration, as given for the bright bottled beers, can entirely compensate for errors in brewing or the use of poor materials, it is certain that much more latitude can be given for such beers both with respect to materials and process. This is not, however, the case with naturally conditioned beers, and the need for the best quality of malt, properly grown and cured and not slack or vitreous cannot be too strongly emphasized, together with a sufficiency of good quality hops and an efficient boil and hop-back filtration. Brewing of beers for naturally conditioned bottling needs particular care and attention. The materials we have dealt with, but the type of wort necessary for the proposed length of storage in maturing is another matter of great importance. The proportion of maltose should not be too great, and there should be a preponderance of malto-dextrin. There must, however, be a sufficiency of dextrin to ensure palate fullness. Mash tun heats must be regulated accordingly, and kept on the high side. Above all, a good strong type of yeast is essential, as a satisfactory fermentation, with ample yeast reproduction and thorough cleansing, is the foundation of satisfactory bottling. There must, of course, be sufficient yeast left in to carry on the secondary fermentation. It is usual to allow a period of two to four months for pale ale to mature in casks. During this time the beer should pass through at least one, probably two, or even three, secondary fermentations. The number of such fermentations depends upon the type and quantity of fermentable matters left in the beer at the time of racking. Strong ales usually require from six to nine months before they acquire that nutty flavour which is their characteristic. They are not ready for bottling until they have acquired it. Where a comparatively sweet stout is in demand it should be ready for bottling after three weeks or a month. The storage of sweet stout should be in casks. When a drier variety is wanted, a period of three to nine months, in a vat if possible, will be found necessary."
"Brewing Theory and Practice" by E.J. Jeffery, 1956, pages 366 - 367.
He's right about only certain types of beers being bottle-conditioned. I wonder how many Brown Ales ever were. Not very many, I think. The need for top-quality raw materials and would have ruled out most of the cheaper types of beer. Brown Ale and Light Ale spring to mind again as good examples. I'd never considered the need to be so careful in the brewing process, but it makes sense. Such beers needed to last much longer than filtered beers that would be consumed immediately. Naturally-conditioned beer would need to be stable (and well-hopped) to cope with the demands placed on it.
I'm glad maturation times are included. Strong Ales seem to have still been matured for surprisingly long periods. Six to nine months doesn't sound much different from 19th century practice. Though I'm sure the volumes of beer being given this treatment were far smaller than in Victorian times. "Nutty flavour". Are there still Strong Ales that taste like that?
Two to four months for Pale Ale. That's down a fair bit from the 19th century, when Bass Pale Ale was matured for 9 months before bottling. Still not bad though. I wonder how many current British beers are aged even two months?
We have mentioned vats in connection with bottling, and we are convinced that, where the volume of trade warrants bottling of the total contents at one time, the use of such vessels induces a beer drinking with greater character and fullness. There is also an advantage in that there is less total ullage than for a similar quantity bottled from separate casks. The disadvantage exists in difficulty of rousing the contents as and when necessary."
"Brewing Theory and Practice" by E.J. Jeffery, 1956, page 367.
Maturing beer in casks and rolling theme every now and again. That sounds just like what they used to do with Courage Russian Stout. They'd kick casks of that around the brewery yard at regular intervals to keep the secondary fermentation going.
I'm sure ageing in vats was more efficient in terms of wastage and probably produced better results. And certainly would have ripened the beer better. London Porter brewers didn't only build huge vats to show off. They appreciated their practical advantages. But most breweries had ripped out their vats before WW I. There can't have been many still in use in the mid-1950's.
"We believe we are correct in saying that a well-known firm which produces stout for bottling not only systematically vats it, but very carefully blends and krausens it as well. Storage in casks or vats for any length of time involves a slower turnover of capital, a factor of considerable importance in these days. Provided that the ultimate price commanded by the bottled article is commensurate with the outlay, then such time as is necessary for proper racking and maturing is fully justified. It must not be forgotten that if any attempt is made to bottle the naturally conditioned beer or stout too soon, there will certainly be trouble. The beer will probably develop a violent fermentation in the bottle, which will introduce a haze. This haze may or may not subsequently clear. A very heavy sediment is certain to form. It not only looks unsightly, but will make the beer very difficult to pour without thickening. This fact, more often than not due to bad bottling, has undoubtedly increased the demand for chilled and filtered beers.
If stout is bottled when too new such violent condition develops that it becomes impossible to pour the contents of the bottle into a glass. Recourse has to be taken to emptying the brown froth into a large jug, and allowing it to settle before transferring it to a glass. A customer who happens to be in a hurry resents such an operation, and is not likely to repeat his order."
"Brewing Theory and Practice" by E.J. Jeffery, 1956, pages 367 - 368.
"a well-known firm which produces stout for bottling" They're talking about Guinness again, aren't they? Were they still vatting their Extra Stout in the 1950's? I know they krausened. That's why above they said that Guinness didn't need to be matured by the bottler. It had already been matured in vats before being shipped to them.