Ultra Cheap HERMS Upgrade

[Birkin]

I don't know how well this sill last, but I've upgraded my infusion mashing setup to HERMS for very little cash..

I already had:
Burco Electric Boiler
Wort Chiller
Infusion Mash tun (Bucket in a bucket style)

I've added:
5M 3/8 ID poly pipe (About £6)
6 Quick connect hose fittings (£1 each from B&Q)
2 10mm to 1/2 inch pipe thread adapters for my wort chiller (£4 off ebay inc postage)
1 12V Diaphragm pump £8 off ebay
Sprinkler head £7 from B&Q
A balloon whisk and hose clip to make a simple secondary filter with my hop bag.

It seems to work well, did a dry (wet!) run earlier to get it up to temp and check for leaks, the diaphragm pump is a bit noisy but it seems to do the trick!

The idea is to use the wort chiller immersed in the boiler to control the mash temp by circulating it through it, and then dump the pump supply pipe into the boiler to sparge (Diaphragm pump can self prime)

Here's what it looks like:

The ballon whisk filter, I have a better idea for this involving a stainless shrimp filter but thats for another day:

The pipe I had lying around, its about 18mm and fits into the back of the tap nicely

I needed a decent 12V power supply, here's my solution:

All ready to go, just need to get some stuff and get a brew in!

From the test drive I have to add that the diaphragm pump is a bit noisy, if it packs in I think i'll find a centrifugal one to replace it, but it was cheap enough.

The plan is to use the boiler to control the mash temp then put the suction pipe into the boiler for sparge (Hence the long pipe). I also made some extra clip on attachments for converting the heat exchanger back to a chiller in seconds.

The thinking is that running the sparge water through the chiller will clean it, then I'll run some boiling water through everything for a few mins to help prevent any nasties from growing between brews.

 

[Spoon]

I was thinking of something like this, couple of questions for you.

1) Do you find there's much temperature drop through the hose returning from the HLT to the Mash tun?

2) Do find much/any temp drop in the sprinkler? One I read where the guy put the temp control probe in the sprinkler and found that evaporative losses in the 'rain' dropped the mash temp by a few degrees, just putting the sprinkler under the water level stopped that and had no impact on the mash because as long as he kept ~40mm water above the grain bed there was no channelling.

 

[Birkin]

From my experiment with water only, I found the mash temp stabilised about 5 degrees below the boiler temp, so I'm guessing about 5 degrees drop. My plan was just to keep the boiler a bit warmer than target and keep an eye on the temps.

I haven't done a mash in it yet though, when I do I'll use loads of temp probes and will then have a better idea

 

[Spoon]

5C is a fair jump, you'd need to be mashing at 61-62C to avoid denaturing beta amylase above 67C be interested to see what sort of fg you get after a brew.

 

[Birkin]

It's not that simple, if you run a pipe through some water a few degrees different in temp it's never going to hit exactly the same temperature, the bigger the temp difference the faster the temp change.

So where there's only a couple of degrees difference it takes much longer to heat the passing liquid.

There's always going to be a temp difference for this reason, the heat loss through the plastic tubes probably accounts for the most part of rest of it, I could always insulate them, keeping them as short as possible is also a good idea.

At the moment I'm guessing at temp drops, I'll get a mash in soon enough and see how it fares, that'll give me a much better idea.

From what I've read about these systems people usually need to keep the boiler a couple of degrees hotter than their mash temp

 

[Birkin]

It seems to work well, main issue I had with it is that the suction hose collapses a bit but it worked well enough to get through the mash, the temp in the mash tun follows the temp in the hlt nicely with no real noticeable lag, maybe half a degree max! Temps top and bottom of the mash tun now come together nicely, they used to drift apart