Wednesday, 23 September 2009

Crazy thought

A crazy thought crept up on me in the tram home tonight. What am I doing? Could I be going too deep?

Truman's weird party-gyling has been puzzling me all week. There seemed no pattern. The wrong-gravity versions weren't always the same. Gravities all over the place. Sometimes over-gravity beers being diluted, others a below-gravity wort being strengthened. And in all sorts of different proportions. For me that rules out flavour as the reason.

Then I noticed something. The few times when they didn't play this game was with two gyles of equal size. Just over 200 barrels. Small batches - under 100 barrels - were invariably blended. Were they just brewing to fill what fermenters they had available? Or to fill them as close as possible to the optimum?

Thinking about this on the tram, as you do, I came up with a plan. I could map out Truman's fermenters, working out their size by what was fermented in them. And because I have loads of photos of consecutive brews, I could map the fermenters across time, seeing which were full. and which free.

Is that crazy? Making a four dimensional virtual map of Truman's fermenting squares? Have I just gone the final step into madness?

I'll report on how the map progresses.


Gary Gillman said...

An interesting plan. The fermenter idea sounds logical. It may have been necessary to run them as full as possible for economic reasons. Or maybe for technical ones: would the squares work properly only half-filled(e.g., re skimming?). Anyway it's a technical issue I think for sure now, not a palate one.


Barm said...

You may be onto something here. It's the only explanation that makes any sense.

Maybe once the data is assembled someone can turn it into a nifty animation showing fermenters being filled and emptied.

Gray Gillman said...

Ron, Lloyd Hind addresses blending in the context of the need to strengthen yeast. He states that yeast quality weakens with consistent production of low gravity brews. One way to increase its vigour is to blend a high strength brew and blend it to finish, thus ensuring yeast quality. I cannot glean the full discussion due to limited views on Google Books. This aspect may have played a role in some of the blending done.

With respect to fermenters, reading shows that skimming was a difficult process, often resulting in loss of beer and (otherwise recoverable and valuable) yeast. Yorkshire squares, for their part, were designed to minimise this loss. While I do not understand their full operation, it seems there is a hole in an interior partition through which the yeast flows up and is decanted off down a sloped surface. This suggests to me that to work properly, they needed to be filled to a prescribed point which would suggest that high gravity brews may have been made to avoid filling a fermenter and a half, say.

Two possible explanations, both plausible. Hind might shed more light on both areas.


Alan said...

Haven't you just moved from a theoretical to practical analysis? If that way be madness, well... And Gary's point is what I understand. The squares when they had that over-flow yeast skimming thing, were logically to work as a capacity - which should provide a standard for your working theory.

First Stater said...

I definitely think a line has been crossed. But it could be interesting to see what is on the other side of that line.

Graham Wheeler said...

I have to say that I do not think that drawing a four-dimensional map would help much. Where is this fourth dimension anyway? I doubt if fermenter size is anything to do with it. Coopers, oak and staves were two-a-penny just across the brewery yard. If they wanted a smaller fermenter they would have built one. It seems that their fermenters were about 40-barrel anyway, not particularly large for an "extensive brewer". As long as a fermenter was filled to greater than 6-feet depth, things would have gone "optimally" in terms of late Victorian ideas at least; home brewers get good results from an 18-inch bucket.

I will maintain that the document probably is not what it seems. There is either a lot more to it or a lot less. If it is anything significant it certainly does not tell the full story. To find out what is really going on needs examination of several similar documents relating to the same beer. Independent confirmation that Pale Ale 1 & 2 actually go out the door at 1055 and 1048 would be nice; I suspect that they do not.

One significant thing is that the blends are always from the same mash. There is absolutely no need to blend beers from the same mash if you are trying to end up with a standardised beer. A brewery the size of Trumans would have several mash tuns and coppers and several parallel brewings going on at once, and each mash tun and copper set would be used in succession four or more times a day. Six coppers could produce 24 brewings a day, minimum, five days a week (Saturdays is always cleaning day). So why do these documents always refer to blending beers from the same mash? It is unlikely to happen in practice.

It is all too neat and tidy, everything that goes in at the top in terms of volume and gravity points comes out at the bottom, exactly, in terms of volume and gravity points. It would tax a modern computer-controlled brew-house to brew to that precision, leave alone a bloke with a blunt pencil and a slide-rule. Besides there are fermentation losses, half the extract is given off as CO2, which has weight and volume, and alcohol is less dense than water, so I would expect the volumes to change if it were a real brewing. It also strikes me that one proportion of the blend is going to end up at an odd gravity that does not match any of their standard products. Importantly, the blends are not identified with a gyle or stock number as the regulations demand.

99 per cent of the Excise regulations are anti-fraud measures. Basically, if the grain going into the brewery does not match the beer coming out of the brewery , within 4%, Excise smell a rat and start throwing their weight around. If less beer appears to come out than the equivalent grain going in, then the brewery is charged duty on the additional grain consumed, over and above the duty on the beer produced. If raw sugar doesn't tally and differs in the wrong direction by more than 2%, there is a fine involved and seizure of the sugar stocks. All this required an awful lot of documentation and calculation on the part of the brewer to show where every pound of extract went. Also, many brewers received an excess materials charge as a matter of course, particularly on high gravity beers and particularly on all malt beers, because meeting the Excise minimum expectation of 80 lbs/qtr extract was not always possible. Small brewers and brewers with less efficient equipment probably never met it. The brewer needed to know what this excess materials charge was going to be, so that he could cost his beer accordingly.

End of part one

Graham Wheeler said...

Part two.

I still feel that this document could be a supporting document of some sort; an accountancy exercise or a double check, not necessarily reflecting what really went on, but simply tracking gravity points of a brewing. Excise want traceability of every single gravity point from the grain going in the door, to the beer coming out of it.

If a brewer consumes more malt or sugar than the Excise regulations deem that he should have done, then they assume that some illicit brewing has taken place and the brewer is charged duty accordingly, on the missing malt.

The brewer has to account for every pound of gravity with full traceability.

From "Statutory Rules and Orders 1923" (the nearest date I could find).

"If the amount of worts deemed to have been brewed by relation to the materials exceeds in quantity and gravity by more than four percentum the worts produced by such materials, the duty shall be charged in respect of the excess over and above the four percentum."

"Forty-two pounds weight of malt or corn of any description, or twenty-eight pounds weight of sugar, shall be deemed the equivalent of a bushel of malt."

On blending:
"When a beer belonging to two or more stocks is blended, a new stock number is to be assigned to the blend. Each cask produced must be marked with the new stock number and also numbered progressively, beginning with No. 1, for each operation."

[The above to be recorded in the "Beer Operations Book" (a warehouse record)]; along with:
"The original gravity of the beer as brewed, or, in the case of blended beer the proportions and original gravities and the proportion of water, if any, entering into the blend"

There are more curious aspects to this than simply performing a blend that is unnecessary.

If it is a blending record, then it should be identified with a blend number. It isn't, not from the image snippet displayed anyway.

Curiouser and curiouser.