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.