Faster stripping with inline wash pre-heater

[GrumbleStill]

Had been reading several threads about continuous stripping rigs and Charentais style pre-heaters, and thought that there might be merit in combining some of the ideas from both to put together an inline pre-heater mostly with stuff I already had in the shed.

My boiler is a 35L 240V 2400W Digiboil and I’d been thinking that using a pre-heater might speed up stripping runs without needing more power. My typical 20-25L strip usually takes about 2.5 hours from flame on to shutdown. The heat up takes up nearly all of the 1st hour, followed by 90 minutes of stripping time.

I figured that I could start with a couple of litres in the pot and get it up to temp in 10 minutes or so then start the pump and run the rest of the wash through in the normal 90 minutes.

Here’s the layout (pardon the terrible drawing skills)

IMG_1240.jpeg

The basic design starts out more or less the same as a 5 plate 4” column with shotgun pc, with the reflux condenser removed.

A variable speed peristaltic pump feeds the wash directly from the fermenter up through the vapour tubes in the shotty and into the column, where it flows onto the top plate.

Vapour is drawn off the top of the column and passes down through the outer shell of the shotty. From there it goes through a regular 3/4 over 1/2” Liebig to make sure the offtake is 100% condensed and cooled.

It ended up looking like this

IMG_1228.jpeg

.

IMG_1227.jpeg

First run was on the weekend, with an all grain vodka wash, and it went really well. I was a bit conservative to start, adding about 4L water to the pot, and running the pump really slow at the beginning, but still managed to take about 30 minutes off the run time.

I was playing with settings a lot during the run, so don’t have definitive stats on exact times and abv’s off the spout, but 300 ml / minute flow rate producing low wines at around 50% abv seemed to be the sweet spot. At 400ml/minute the boil collapsed.

The temperature in the pot remained stable at water boiling temp throughout the run.

Next time round I’ll try back to back strips of sugar wash to see how much I can speed up the day. The idea is that I’ll just switch off the feed pump and drain the boiler down between runs. The boiler holds a few litres below the drain, so I don’t need to worry about it running dry.