I just want to get one thing off my chest before we start. Coolship is not an English word. It’s a translation of the German or Dutch – Kuhlschiff or koelschip. It’s really irritating when people don’t use the correct English word.
Though by the 1950’s coolers were no longer widely used. In the early 19th century coolers had been the only devices used to cool wort. After the development of refrigerators – a system of pipes through which flowed cold water or brine and over which the wort flowed – these were used in conjunction with coolers rather than replacing them. Partly because coolers still had an important auxiliary role in precipitating out gunk from the wort.
“Wort Receiver. If the brewery is suitably arranged, the wort can pass by gravitation to the wort receiver and thence to the refrigerators. Some brewers consider that the use of a pump between hop-back and refrigerator has an undesirable effect upon the colloidal matter in the wort, dispersing it into smaller particles which may affect the yeast in the fermentation: undeniably, if hop-back filtration is poor, insoluble particles in the wort may get broken up in the pump; but such insoluble matter from the hop-back is objectionable in any case, whether or not its adverse effects are increased if it is in smaller particles. Be that is it may, the amount of such insoluble matter in a wort should be negligible; if it is not, the remedy is to be found in improved hop-back filtration. The present author considers that this objection to pumping is without foundation, and the fact of the matter is that many, if not most, modern breweries pump their wort, either to raise it to a wort receiver on a higher floor, or for the purpose of obtaining sufficient pressure for use with an enclosed refrigerator to get an adequate throughput. “
"Brewing Theory and Practice" by E. J. Jeffery, 1956, page 47.
It sounds here as if the hop-back had replaced the cooler in the function of removing crap from the wort.
Here’s a little more about coolers:
“At one time the wort would have been discharged into a large shallow cooler. The latter was undeniably necessary before the advent of refrigerators. Exposure of the wort to the air, in a shallow vessel, was the only means of cooling in those days. But during that time the wort could pick up innumerable bacteria and wild yeast, a most undesirable feature. The extensive exposed surface of wort was open to infection from any local sources which might exist. In many cases where receivers were substituted for coolers there was an immediate improvement in the quality of the beer. Open coolers are now hardly ever used in top fermentation breweries. A few breweries however still use them, on the grounds that they provide conditions of cooling and an opportunity for sedimentation that are beneficial to the wort. Lager breweries still use them extensively and they are usually housed in enclosed rooms supplied with sterile air.”
"Brewing Theory and Practice" by E. J. Jeffery, 1956, pages 47 - 48.
That’s interesting about Lager breweries still retaining coolers. I guess if they were placed in a closed room, much of the risk of infection with wild yeast was removed. Though the operational coolers I’ve seen in Germany weren’t housed this way. They were just parked next to the copper. Unlike the open fermenters, which were in sealed, refrigerated rooms.
“A receiver is only an intermediate vessel between the hop-back and the refrigerator, and it does not act as a cooler, since it is usually a fairly deep vessel. It must be of sufficient capacity to ensure a regular flow and delivery of wort to the refrigerator. If a spreader in the shape of a dished circular metal plate is fixed at the mouth of the inlet pipe, a certain amount of hot aeration may be effected at this point. Alternatively, the same result may be obtained by discharging at the delivery end into a trough of perforated copper which splits up the wort. This hot aeration is most beneficial towards the subsequent fermentation. Adequate aeration can however usually be effected at the hot end of the refrigerators.”
"Brewing Theory and Practice" by E. J. Jeffery, 1956, page 48.
Hot-side aeration - isn’t that one of the things home brewers go on about endlessly? About how bad it is. While professional brewers have spoken to say that’s bollocks. I see Jefferey is firmly in the pro hot-side aeration camp.
Not sure what will come next. Maybe fermenters.