Tuesday, 27 August 2013

Bottling in 1901: maturation after bottling

What a week it's been. I've stubbed my toe twice on important discoveries. I think I might have cracked my big toe, they were so weighty

The first I didn't notice when I first read the article. It's just an innocuous little entry in a table. But it's confirmed a suspicion I've held for a while, but haven't been able to find any evidence to back up. What is it I've discovered? That SA malt stands for "Strong Ale" malt.

Having seen how SA malt was used - almost exclusively in Strong Ales - had made guessing the meaning a bit of a no-brainer. But it's still nice to have confirmation. What's really got me excited, it is finding some detail about the characteristics of SA malt. You can see it in this table:

Table I.
A. Malts.
Pale ale. Mild ale. Strong ale.
Easily fermentable matter. 60.5 64 57
Difficultly „ „ . 16.5 16 17
Unfermentable „ . 23 20 26

B. Bottled Pale Ales.
At bottling. 6 weeks old. 12 months old.
Fermented solids 60 = 77% of F.S. 65.0 = 80% of F.S. 69 = 87% of F.S.
Fermentable residue 18 = 45% of R. 13.5 = 39% of R. 10 = 32% of R.
Unfermentable „  22 = 55% of R. 21.5 = 61% of R. 21 = 68% of R.

C. Bottled Strong Ales.
At bottling. 6 months old. 2 years old.
Fermented solids 55 = 73% of F.S. 60 = 79% of F.S. 62 = 80% of F.S.
Fermentable residue 20 = 44% of R. 16 = 40% of R. 15 = 40% of R.
Unfermentable „  25 = 56% of R. 24 = 60% of R. 23 = 60% of R.

F.S. = Fermentable solids. R. = Unfermented residue.
Journal of the Federated Institutes of Brewing, Volume 7, Issue 2, March-April 1901, page 194.

OK, the information is pretty limited. But it does tell us that SA malt contained more unfermentable material than mild ale malt or pale ale malt. That explains the high finishing gravities of KK and KKK then. K Ales often used SA malt as their base malt. What would be the modern equivalent, I wonder?

I was very surprised to see that mild ale malt contained more fermentable material than pale ale malt. I would have expected it to be the other way around.

The rest of the table is also damn interesting, because it highlights the different maturation periods of Pale Ale and Strong Ale.
"Table I places side by side analyses of pale and strong ales made at different periods: the gradual alteration in composition is very marked.

The time required to produce first-class bottled strong ale is in all cases very much more than for pale ales, and beers vary very much in this respect, but in the first place a strong ale should remain in the brewery cellar for not less than six months, and after removing to the bottling store will probably take a month or six weeks to get into fit condition for bottling. After bottling it may take fully six months more to properly condition, and care must be taken that the corks do not get dry.

It is, I am sorry to say, quite a rare thing to see a bottle of strong ale in perfect condition, and I think if more care were taken in this respect there would be a much greater demand for this, the finest product of the brewery.

As the best bottling stout is usually vatted and it is not required to be brilliant, the conditions of bottling are somewhat different, but I do not propose discussing this question."
Journal of the Federated Institutes of Brewing, Volume 7, Issue 2, March-April 1901, page 195.
I've explained before the lengthy process of producing a Stock Pale Ale, one which could take more than 12 months. It seems that it took even longer to make a properly-matured Strong Ale. The article seems to say that 12 months is the minimum time required to produce such a beer. Something which it sounds like most breweries couldn't be bothered or couldn't afford to do.

The analyses after different periods of ageing are fascinating. You can see that a considerable amount of fermentation went on after bottling and continued for a very long time. We can see just how much by doing a few calculations.

Assuming that the first number for fermented solids is the real attenuation, it's easy enough to work out how the gravity fell after bottling. For Pale Ale, I've assumed the classic 1065º gravity. For the Strong Ale I've been more specific, taking the OG from Whitbread and Barclay Perkins KKK of the period, both of which had an OG of 1087º. The first FG, 1027º, is very close to the racking gravity of Barclay Perkins KKK, which was 1026.3º.

Here are the results in a nice compact table:

OG FG ABV Apparent attenuation real attenuation
Pale Ale at bottling 1065 1016.5 6.32 74.62% 60.14%
Pale Ale 6 weeks after bottling 1065 1013 6.79 80.00% 64.70%
Pale Ale 6 months after bottling 1065 1010 7.21 84.62% 68.63%
Strong Ale at Bottling 1087 1027 7.81 68.97% 55.07%
Strong Ale 6 months after bottling 1087 1022 8.50 74.71% 59.93%
Strong Ale 2 years after bottling 1087 1020 8.78 77.01% 61.89%

You can see that after bottling, the ABV of both beers rose by almost 1%.

This helps me understand much better the analyses of 19th century Pale Ale where the apparent attenuation is well over 80%. At racking time, it might well have been no more than 75%. It's a new insight into the long process of producing truly bottle-conditioned beers.

The fall in the unfermentable residue of the Strong Ale I can only attribute to one cause: the action of something other than Saccharomyces, probably Brettanomyces. Not really a surprise in a beer that had been left a long time maturing in wood.

I don't know whether you'll be delighted or driven to despair when I tell you that I've barely scratched the surface of this article yet.


Gary Gillman said...

That is interesting. Perhaps they had ways to process malt, or were using different barley qualities to begin with, where the colour scheme didn't denote a strict gradation of extract weight. E.g. I would think it unlikely that the strong ale malt was always paler (thus richer in extract supposedly) than the others. Certainly the mild ale by this time was darker than the pale ale malt, perhaps much darker, yet it contained more fermentable starch. So high quality barley was used or more likely I think, different kiln treatment was applied. Does he actually says "strong ale malt" in the article though? Or is it an inference from strong ale having its own type of malt (clearly)?


Edd Draper said...

Just looking at modern malts for comparison, the champion these days would be something like Maris Otter pale malt, which weighs in at around 83% yield. The other pale malts fall in the 78-82% range, with darker malts like Mild Malt below that and higher-kilned malts such as Munich coming up the rear. Certainly we play with much higher quality varieties of barley today than appear in your table from 100 years ago. It is often said that Amber and Brown malts were different back then compared to today, as theirs were fermentable and our modern versions are not, having no diatastic power at all. It's not a stretch to posit that Victorian Mild Malt was different than our modern version of it too. I have read that the higher kilning temp of Mild malt was used to get a more malty or nutty flavour than Pale malt. That is quite useful in modern weak milds, but probably would not have been necessary in the giant Victorian ones.

You did say in your Brief History of British Beer that Mild was by far the most popular drink around at that time, and so they had to make a lot of it. I suppose it could make sense to use the most efficient malt available for their most produced beer. Wasn't it true going further back that breweries switched from Amber and Brown to Pale malt because, in spite of the increased cost, its increase in efficiency more than offset that. Perhaps on a smaller scale that is also true here.

I am wondering also if Strong Ale malt was analogous in any way to a higher kilned modern malt such as Munich, which we find today further down the list from Pale and Mild, and which would give 2-3 times the colour extracted from the Paler malts. I don't suppose there's any way for us to ever find out how highly kilned those old grains were?

Ron Pattinson said...


I wish I did have more exact information about the colour of the malt and how it was kilned.

It's quite possible that the composition of mild malt changed over time. Brown malt certainly did, and in more ways than just going from diastatic to non-diastatic.

I guess the records of maltsters are where the answers to these questions lie.

Gary Gillman said...

Since the strong ale malt had a higher degree of unfermentables, it is reasonable IMO to suppose - despite what I said earlier - that it was darker than pale malt.

I agree with Edd it might have resembled the modern and self-converting Munich, and this is why I still think SA could mean special amber i.e. diastatic amber. To be sure the table states that there is a malt for strong ale but that doesn't mean SA means strong ale malt - it may well do so, but not necessarily.


Ron Pattinson said...


in the records, I've come across PA malt, MA malt and SA malt. The table in the article has columns for pale, mild and strong malts.

That's pretty good evidence to me that SA stands for Strong Ale. Especiially as in the brewing records it's almost exclusively used in Strong Ales.

Surely it would have been more likely to call diastatic amber malt DA - diastatic amber?