Guinness’s Park Royal Brewery in 1949 – the brew house (part four)

Don’t worry. Our slow crawl through the brew house will soon be over. Of course, that’s far from the end of our visit to Park Royal.

Nearly as important as the coppers themselves were the hop back, where the hops ended up after boiling.

“There are two hop backs each of 800 barrels capacity of more or less orthodox design in that they are circular vessels of about 26 ft. 6 in. in diameter and 9 ft. deep, constructed in copper bearing steel to resist corrosion and the usual gun-metal false bottom plates, the slots being 19 s.w.g. i.e. 0.040 in. The hop backs have copper domes with a chimney taken up through the roof for disposing of the vapour to outside the brew house. Disposal of the hop-back vapour in this way appreciably reduces the maintenance of the building steel work, etc. Perhaps an interesting feature is that the hop backs are fitted with revolving rakes for putting out the spent hops. A small dip of weak worts is put into the vessel, the rakes revolved to mix thoroughly the content, and then the hop outlet is opened to a centrifugal "free flow" pump which pumps the spent hops over to the by-products department for draining and drying. The same pumping system is used for returning hops to copper for alternate boilings. The hopped wort from the hop backs is pumped up to the wort coolers which are large open vessels about 26 ft. X 24 ft. and 6 ft. deep, constructed in copper bearing mild steel and located on the top floor of the brewhouse. They are open to the atmosphere.”
Journal of the Institute of Brewing Volume 55, Issue 5, 1949, pages 282 - 283.

Some revealing stuff there. For a start, they hop sparged. That’s what the bit about “a small dip of weak worts”. That means they were adding a low-gravity wort to extract the wort retained by the hops. This was presumably higher gravity than the wort used to flush it out. More surprising was the fact that they returned hops to the copper, i.e. they were reusing spent hops. Very odd at this late date.

Note that they were still using open coolers, despite having refrigerators for cooling wort. Coolers (not fucking coolships) remained in use because, in addition to cooling wort, they were useful in removing all sorts of gunk from the wort. Being very shallow, sediment dropped out more quickly. As was usual, they were located at the top of the brewery, where the flow of air was best.

Not that coolers cooled the wort that, er, cool:

“The wort lies here where atmospheric cooling is allowed to lower the temperature to 176° F., which ensures that the temperature, when running down, does not fall below a safe figure. The wort is discharged into the wort coolers over aeration hoods.”
Journal of the Institute of Brewing Volume 55, Issue 5, 1949, page 283.

Aeration hoods? Surely you wouldn’t want to aerate the wort at this point? Would you? I guess by wort coolers they mean refrigerators, whose form and function I described earlier.

Not sure what’s next. Something.