Thursday, 14 January 2016

Guinness’s Park Royal Brewery in 1949 – the malt store

We’re back inside Park Royal, poking around its buildings, seeing what we can find. Oh look – it’s where they store the malt.

“The malt store.—As constructed, the malt store can hold some 125,000 quarters, using both the main and auxiliary silos, the latter being in the inter-spaces between the main circular silos.”
Journal of the Institute of Brewing Volume 55, Issue 5, 1949, page 279.

125,000 quarters? That’s a huge amount of malt. Want to know how much Guinness Extra Stout you could brew with that? An awful lot. It just so happens that I know the OG of Extra Stout in this period:

Guinness bottled Stout 1948 - 1951
Year Beer Price per pint d OG FG ABV App. Atten-uation colour
1948 Extra Stout 15.5 1047.2 1012 4.57 74.58% 1 + 6.5
1948 Export Stout 1072 1019.1 6.89 73.47% 1 + 10
1948 Extra Stout 24 1045.2 1012.6 4.23 72.12% 1 + 9
1950 Extra Stout 23 1048.6 1008.6 5.21 82.30% 1 + 8
1951 Extra Stout 30 1049.1 1007.5 5.43 84.73% 1 + 8
1951 Extra Stout 30.5 1047.7 1008.1 5.16 83.02% 1 + 8.5
Source:
Whitbread Gravity book held at the London Metropolitan Archives, document number LMA/4453/D/02/002.

The OG averages out to 1047.6º, or 17.1 lbs per barrel. Assuming 90 lbs extract per quarter, I make that 5.26 barrels per quarter of malt. Meaning the whole malt store held enough to brew 657,590 barrels.  Remember the expected “normal” annual production was 650,000 barrels. It looks to me like they deliberately built the store big enough to hold a year’s supply of malt.

It was also a huge weight. At 336 lbs per quarter, the store could hold 18,750 tons of malt. No wonder it was built like a brick shithouse. As we’ll now see:

“The malt store building is about 100 ft. high, the silos being of reinforced concrete masked by brickwork panelling. There are 127 silos each 12 ft. diameter by 65 ft. deep and holding approximately 760 quarters each, and there are 105 inter-space silos, with capacity varying from 130 to 165 quarters. Particular interest attaches to the construction of the reinforced concrete silos in the malt store, as they were among the first to be built in this country on the moving form principle with the concrete being continuously poured. The complete structure was erected in 13 days, the average speed of the erection being 5 ft. per day. In this method of construction, timber formers are built to the size and shape of the silos and lifted slowly by jacks as the concrete is continuously poured. It ensures not only rapidity of erection, but also a continuous smooth surface free from any joints which might arise from different setting consistencies of concrete inevitable in the fixed shuttering and batch pouring system.”
Journal of the Institute of Brewing Volume 55, Issue 5, 1949, pages 279 - 280.

Not sure what to say about that. But it sounds very modern in construction with all that concrete. You have to be very careful about how you store malt, as the dust form it can explode when exposed to a naked flame. Which is one reason you might want to avoid making silos from metal.

“The intake system had to be designed to receive by road or rail five different grades of malt simultaneously from different sources of supply, and to keep them separate through the screens and ultimately to the storage silos. To allow of this being done, the intake system was arranged in five separate units, each having a capacity of 250 quarters per hour and consisting of:—intake elevators; weighing machines before and after screening; magnetic separators; wire cylinder screens for cleaning and grading; suction filter dust collecting plant; and delivery elevators. Malt can be taken in at any unit, to be cleaned, screened and weighed, after which it is delivered to any one of the storage silos by means of the bucket elevators and the belt conveyor system. The stored malt can be turned over or recleaned whenever necessary. Similarly, malt can be drawn from any silo, to be weighed and passed over to the brewhouse mills.”
Journal of the Institute of Brewing Volume 55, Issue 5, 1949, page 280.

Five different grades of malt? I’m pretty sure Guinness at this period used no more than two types of malt: pale malt and black malt or roasted barley. The system described sounds very efficient and automated. Which I guess is the advantage to building the brewery from scratch.

Next we’ll be looking at the intake system in more detail.

12 comments:

StuartP said...

That is a lot of relatively small silos.
There are some old, redundant, concrete grain silos near me that are huge mothers.
I don't think anyone has come up with a way to 'un-build' them yet.

Moaneschien/Ingo said...

Quite a jump in attenuation.

Ron Pattinson said...

Moaneschien/Ingo,

you're witnessing the birth of Dry Irish Stout.

Anonymous said...

Would grades of malt be different from type? A lot of agricultural products are separated by grade so that higher quality stuff with less stems and chaff and broken bits gets sold for a higher price.

J. Karanka said...

By grades do they refer to qualities of pale malt as well? I assume they used some portion of cheapo malt like many breweries.

Moaneschien/Ingo said...

Ron,

you probably have it posted somewhere on the blog before (I get lost) what was the process change that got them the increased attenuation? Change of grist, mashing, yeast?

Ron Pattinson said...

Anonymous & J, Karanka,

yes, it could well be different grades. In brewing logs you often see No. 1 and No. 2 categorising pale malt.

Ron Pattinson said...

Moaneschien/Ingo,

I've no idea what the change was that increased the rate of attenuation, unfortunately. I can just see it change in analyses.

Mike Austin said...

The start /increase of flaked barley?

Ron Pattinson said...

Mike Austin,

I don't think they started using it until the 1980's.

Mike Austin said...

We've had this conversation before! Dave Line's home brewing books in the early 1970s include 20% of the stuff. According to Boak and Bailey, he had help from Guinness. It must have been earlier than the 80's
And it would explain it, wouldn't it?

Ron Pattinson said...

Mike Austin,

the answer is sometime before 1972. According to David Hughes in "A Bottle of Guinness Please", by 1972 both the Dublin and Park Royal breweries were using flaked barley.