Monday, 14 November 2016

Cold liquor tank working well.... just in time for Winter!

Well, we knew this was going to be the situation we found ourselves in, and in many ways it's quite amusing.... and in other ways quite annoying.....

It concerns our major project this year, the cold liquor tank, which would have been ideal to have been in service during the summer and autumn when mains water runs warm.  So what, you may say, who cares what temperature the water coming out of the tap is?  What does that matter?

Well, to that I'd say shut up and listen.....  most small brewers use mains water to power their plate heat exchanger (PHE or paraflow in brewer's parlance) which is a terribly useful and also quite mysterious device which takes in water and hot wort from the copper at one end, and spits out hot water and cold wort at the other.... quite how it does it remains a mystery to me (yeah, yeah, I could look it up but that would spoil the mystery, and I know the basics anyhow) but, and here's the crux of the matter, the PHE can only cool wort to "pitching temperature" (around 22°c for us, we run off warm then use the chillers on the FV to bring the temperature down to 18.5°c) at a speed governed by the temperature of the water coming in which, in Autumn, can reach almost 20°c which can mean running off 1500 litres of wort to FV can take almost 2 hours at a pitiful 12 litres a minute which means it's scarcely dribbling out of the aerator!

So, in steps our flashy CLT (cold liqor tank) which solves this problem by using a chiller unit to cool water stored in the 3200 litre bulk milk tank via a coiled copper tube immersed in said water.  This resulting cold water (at around 5°c rather than mains at over 10°c) means the PHE can cool the wort much faster and has reduced the 1500 litre transfer time down to 40 minutes or so, a massive saving in time and much less standing around for us....

However, as you'd expect, in Winter the mains water starts to become a lot colder and the water can - in Jan and Feb in particular - be entering the brewery at around 6 or 7°c which means we don't really need the CLT!  Saying that, at present it's bringing our cold liquor down to nearly 5°c which is very impressive and means, for now at least until the weather gets really cold, we can transfer in just over half an hour at 37.5 litres a minute!  

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