Wednesday, June 22, 2011

Upgrade plans

There are some problems with the fresh water delivery part of the brewbot.

a) The quick disconnect I was using for connecting the brewing vessel to the water supply ended up containing some steel which had began to rust.

b) The clear PVC hose I was using was not up to mains water pressure and eventually burst.

c) The water delivery rate was too high and I was using a small tap on the Y-piece in the laundry to control the flow rate. This was difficult to tweak.

So the solution is to move to a braided dishwasher hose, new 1/4" all brass solenoid and standard corny keg quick disconnects. I'm hoping the smaller 1/4" solenoid and corny fittings will reduce the flow rate sufficiently.

While not a huge problem, we were also seeing a fair bit of trub in our final wort.

My mates over at are all about the Speidels Braumeister. Interestingly this is what inspired BIAB back in 2006.

This system is a single vessel system that recirculates the wort for the duration of the mash. The grain bed catches a lot of protein and particulate leaving very clear wort.

I'm interested in experimenting with this technique in a different configuration for the brewbot.

Instead of having an impeller based pump sit under the vessel, I'm thinking of having a peristaltic pump mounted above the vessel with hoses attached to the lid that lower with it.

The peristaltic pump should be able to self prime and hopefully deal with any fine grain particles.

The new mash process would be:

a) lower the grist bag into the strike water
b) stir the mash for the first 5-10 minutes
c) run the peristaltic pump for the remainder of the mash
d) raise the grist bag

The mash would be a RIMs effectively.

Unfortunately most cheaply available peristaltic pumps offer pretty low flow rates. The ones that offer higher rates are both expensive and bulky.

So I'm going to have a go at building a ghetto version with the silicon hose I have, some small ball bearing and another windscreen wiper motor. I'd kill for a lathe, or even a drill press at the moment, but hopefully I get something going to prove the concept.

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