15l Stovetop Herms

[Tim F]

Hey all,

I've been thinking about getting into HERMS for a while now and started putting together the bits for a system.

I don't drink tons of beer every night but I like making it and trying new styles so a smaller system is just fine - I reckon I'll get 10-12L batches out of a 15L tun easily. I also want to use this for cooking sous vide so if it fits in the kitchen its a bonus. Also budget is important atm so it's pretty ghetto

The plan is:

15L stock pot for mash tun. I will insulate this with a camping mat or something. Got the brass nipples for inlet/outlet and plan to attach ball valves with hose barb to them.

False bottom - I have a few options. One would be just to buy a sheet of stainless screen and sit it on legs above the height of the outlet. But I was really thinking about grabbing a 10L stock pot, welding a couple of little legs on it and drilling holes in the bottom. If I did that, and didn't sparge, I could just lift out the grain and boil right there in the mash tun. The plan is just to boil on the stovetop, don't think ~12L boil volume will be an issue on the stove. If it is I have a 2 ring burner too.

Pump etc - tubing between vessels will be 12mm OD silicon, which is the biggest I can fit in my existing peristaltic pump. I think I can coax 2L/minute out of my pump but if that doesn't cut it I will get one of these. I plan to insulate the silicon hose as well. Haven't really thought about the return arm yet but maybe just an extended copper T sittin on the grain bed?

Heat exchanger - I bought a cheap ass kettle thinking I'd use the 1800W element in a saucepan. But then I thought why reinvent the wheel, and wound a coil to fit in the kettle itself! I got 2m of 1/2" copper pipe coiled in there and will drill holes in the side of the kettle, connecting the coil to brass nipples with compression fittings, and use silicon washers + aquarium silicon if needed to seal the brass nipples in. If that coil doesn't work in the kettle I'll go back to plan A and pull out the element for a bigger HEX and coil but I don't think I'd need to go too much bigger for such a small system?



Temperature control - I gave up on the idea of controlling the system by laptop + VBA PID for now and ordered one of the cheapy PIDs off ebay. I'll do the standard temp probe in a T piece on the HEX outlet and run the kettle via relay from the PID.

The only flow switching I might want to do is if I do boil in a separate kettle so I might just have another T on the HEX outlet with 2 ball valves, so after mashout I just swap those 2 valves, drain to kettle and boil. So yeah it's about as simple as you can get - straight loop from bottom of MT through HEX and back to the top of the MT, and then either swap outlet to drain to kettle OR lift out grain, preheat with the HEX, then plonk the MT on the stove. What do you reckon?

I'll post more of the build as parts arrive from round the world via ebay

 

[Maheel]

i wouldn't drill the kettle . but thats me...

can you add a 90' elbow on the bottom and run the coil back out the top ?
just reckon you might get leaks (and elbow might be easy)

 

[Tim F]

I could do that and did wonder about just dropping the coil in over the top of the kettle but end of the day I don't really mind if the kettle breaks or leaks, it was only $12 and I still get the element

But yeah it is a real chance I will have issues with the kettle wall being curved and fragile, I won't want to do up the nuts too tight so thought maybe I'd just do it up snug and cover it in silicon.

The other option is we have a nicer stainless kettle that has a slow leak. If the plastic one is no good I might tell the missus we need a new one, silicon up the the metal one and use that.

 

[Tim F]

Well, I went for it. No problems drilling out the holes, that plastic is less brittle than it looks. Not going to silicon the fittings in yet though as I am waiting for 1/2" female BSP to 10mm hose barb adapters to arrive off ebay and not sure how deep the threaded section will be on those - I might be able to get away without using the nuts at all there and just rely on the adapters to hold the nipples tight.

Jeez its all a bit raunchy isn't it, silicon, tight nipples, nuts, female adapters...

 

[Tanga]

Very interesting. I look forward to seeing what happens with this. I have that exact same kettle. Another option if that hadn't worked (as it obviously did) is a cheap old aluminum kettle from an op-shop. They're usually a bit bigger too. How much are all those connections / where did you get them? Why are you going this way instead of BIAB?

 

[Tim F]

Well there might still be a touch of biab in the final design, one idea was to put the grain in a bag in the tun and recirc through that. The reason I didn't just use an urn though is because I like the easy temperature control for step mashing with the pid and I like the idea of keeping the water recirculating to boost efficiency.

 

[Acasta]

Genius. Looks awesome. Good work.

 

[glassgrenade]

what is the point of this? I'm sure this will work, but i can't see where your gains are going to be over a normal stovetop biab mash. You won't get an increase of wort clarity if you use a bag. You won't be saving money on equipment (the whole point of stove top mash) if you have to buy a pump and a false bottom. And with such a small thermal mass i think that the temp of this thing is going to be shooting all over the place, so you won't be getting the smooth stable temp that is the whole point of a herms. I'm not trying to shoot you down in any way, i just really don't understand the whole pint of this brewing system you're making, to me it seems like a whole lot of expenditure for little gain.

If its just to see if you can, then i understand that, i'm a tinkerer myself.

 

[Dazza88]

But it is cool.

 

[Tim F]

what is the point of this? I'm sure this will work, but i can't see where your gains are going to be over a normal stovetop biab mash. You won't get an increase of wort clarity if you use a bag.

I most likely won't use a bag, that was just a vague thought if my other ideas don't work. The idea I like most so far is to use a 10L stock pot with the bottom drilled full of holes, effectively a false bottom that can be lifted out.

You won't be saving money on equipment (the whole point of stove top mash) if you have to buy a pump and a false bottom.

The whole cost of the system is $100 and change. I already have a peristaltic pump but if that doesn't work it will be + another $30 for one of those cheapy pumps.

And with such a small thermal mass i think that the temp of this thing is going to be shooting all over the place, so you won't be getting the smooth stable temp that is the whole point of a herms.

I'm not so sure about that, the thermal mass is smaller but people hold 1C in a 20L BIAB for an hour, if I insulate properly and exchange the whole mash volume in about 5-7 minutes I think it will be very stable in there. But yeah I will need to insulate everything possible. I also love the idea of step mashing without extra infusions or decoctions.

I'm not trying to shoot you down in any way, i just really don't understand the whole pint of this brewing system you're making, to me it seems like a whole lot of expenditure for little gain.

If its just to see if you can, then i understand that, i'm a tinkerer myself.

Well yeah a big part of it is just tinkering - I needed a new project and this was a good one. I also wanted to try cooking sous vide, in fact that was my first reason to start building this before I realised it would only need a few mods to brew in as well! I already have a traditional 40L AG setup so not relying on this as my only source of beer anyway if it doesn't work out

 

[_HOME_BREW_WALLACE_]

Nice work! :icon_cheers:

What did you coil your copper around?

 

[Tim F]

Don't laugh - a piece of firewood I also discovered that if you fill copper pipe with damp sand, then coil it up, the wet sand is very hard to get out. The missus just rolled her eyes.

 

[dent]

This thing looks good -

The heat exchanger will work fine - I use a similar sized one for a 50L system. You won't have any problems with the thermal mass or temperature stability, your PID controller will establish the duty cycle required to maintain your temperature very accurately.

 

[yardy]

the wet sand is very hard to get out.

try salt next time, just flush it out with hot water.

nice little project by the way, had to laugh at the 'why are you doing this' and 'why not BIAB' comments though

cheers

 

[Tim F]

try salt next time, just flush it out with hot water.

Great idea, cheers!

 

[Tanga]

try salt next time, just flush it out with hot water.

nice little project by the way, had to laugh at the 'why are you doing this' and 'why not BIAB' comments though

cheers

Wasn't having a go, just curious about what the advantages might be. My understanding of HERMS is sketchy. I find it all very interesting though.

As an alternative to drilling holes in a pot another alternative discussed in BIAB threads is a large steaming basket from a Chinese shop.

 

[pk.sax]

http://www.bcf.com.au/online-store/product...769#Description

This might be an easier conversion Tanga. Almost all the biab basics present in the setup, modify the crab cooker insert, maybe with a bag. There is a 22.5 L version slightly cheaper too.

 

[Tim F]

Slowly getting more bits, got the silicon hose today.

Does anyone have opinions on the pot-in-pot design? I'm leaning that way as I found a bigger pot in the shed that my 15L just fits in to - and it even has the right size hole drilled in it already for a 1/2" nipple The plan would be to drill the bottom of the pot full of ~2mm holes, then sit it above the bottom of the other pot on a stand or legs. I might be able to use my dads CNC router with a drill bit to drill the base of the pot so could get them pretty close and neat. I know people already do this with the old bucket in a bucket tun design, would it drain quick enough if I'm pumping from underneath the inner bucket?

Here's how the flow would go:



Also I am pretty tempted by this little pump - reckon it would do the job?

 

[Tanga]

The head (how high it can pump) is plenty @ 1.6 m. Is 1.5 L / min enough throughput? You (probably) won't get a stuck spare at that speed, but will it be enough to ramp the temp?

 

[Tim F]

Well if I have a 10L mash volume it will recirc the whole lot in 6 and a half minutes which seems ok, 15L in 10 minutes obviously, I think thats somewhere around the same time to recirculate as bigger systems???