Wednesday, 21 January 2009

More Pump Action

A welcome break in the recent freezing weather last weekend meant it was high time for another Racking-off & Topping-up session. By racking-off we aim to remove the young, slowly clearing cider, from the old yeast deposit which should by now have settled at the bottom of the fermenter. The cold conditions won't harm the cider, but this session of racking-off involved the transfer of over 1000 litres of cider, a process likely to take most of the day and therefore not a job to be undertaken in bone-chilling sub-zero temperatures.

The time had come to plumb our shiny new pump into couple of lengths of food-grade tubing, and get down to some serious suction in the ciderhouse. The pump performed very well, sucking up the cider without disturbing the sediment, and squirting it into the fresh tub at a (slightly worryingly) high rate. The Okoflow 3000 pump has a flow rating of 50 litres/minute, which I found to be pretty accurate. One of our 120 litre fermenters was taking no more than 2-3 minutes to transfer, the bulk of the time throughout the day was spent cleaning and sterilising the tubs ready for the next batch of cider to be racked-off. This is considerably quicker than syphoning using gravity alone, a 70 litre fermenter racked-off in this way was taking around 10 minutes last year, and I would have struggled to complete the job in a day without the use of the pump.

The one possible disadvantage of using a pump to rack-off the cider, is the vigour of the transfer. The cider is sucked into the pump chamber clear and relatively un-agitated, but emerges in the other tube fizzing with tiny bubbles. This is the dissolved CO2 being liberated from the cider by the spinning impeller of the pump, a bit like twizzling a straw in a fizzy drink. We aim to keep as much of this dissolved CO2 in the cider at this stage, it helps to protect the cider from oxidisation and the possibility of bacterial infection. But even so, the cider should still have enough dissolved CO2 to protect it, and the warmer months of Spring will inevitably lead to a period of gentle fermentation which will also help.

I'm not the only cidermaker with pumps and racking-off on his mind. The ukcider discussion forum, the essential online destination for anyone with an interest in cider or cidermaking, is currently host to a lively debate on the relative merits of a wide assortment pumps. Perhaps not the most exciting discussion you're likely to find on ukcider, but it could be worse. A discussion on the merits of cider on the ukpumps* forum anyone?

*I made up the ukpumps forum, though I wouldn't be at all surprised to find that one really does exist!

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