Watney's Mortlake. Brewing School visits 1968 to 1969
Visit by Brewing School students in January 1969
Traditional plant, 16 to 17,000 barrels per week. Large number of products (some for export) from brews running into FV which is an intricate job. Open sided coppers which are oil fired and a vigorous boil is claimed, but must be difficult since level came to less than two feet from the brim! Rectangular open hop backs of wartime design. Hops are collected and added back at conditioning.
Traditional FVs, some have resin lining in a concrete former. Easily dented by careless cleaners. Lager for export only in the same fermentation room as top fermenting yeast brews.
There is a continuous fermentation system for Watneys Special Bitter and Red Barrel which operates as follows:-
The plant works at 10 barrels per hour and it takes 36 hours for the work to pass so the plant produces 6,000 barrels per week. Potassium carbonate brine is used to cool FVs.
There is no warm conditioning. Beer is chilled and stored two days before fining. It is filtered mixed with Polyclar AT and refiltered. The AT is recovered with a caustic wash. Beer is pasteurised into keg or tank. Kegs are steamed for one minute to increase the temperature to 185°F followed by a 30 second dose of CO2. Tankers are weighed in an out of the brewery.
There is also a 1,000 barrel per week experimental continuous brewhouse currently closed for economic reasons. Need one line for each beer produced by such a process. Carefully metered liquor and grist. Boby mill works continuously which is greatly in excess of the manufacturers expectations. Pump through mash holding tubes fixed residence time at a fixed temperature. Final high temperature destroys enzymes. Rotary mash filter for run off with eight valentine tubes to control. Greatest differential pressure at the final sparge to get last extract from the grains. Later run off used to sparge the new mash. Buckets empty into spent grain system. There are eight buckets so one bucket every 15 minutes. Boiling wort passes over two consecutive hop beds which allows changing when spent. Good utilisation. Wort was metered for Excise by filling collecting vessels and a small sample was taken before emptying and fermentation took place in an APV tower.