StillSmart

I know there are a few folks on here that have an interest in all grain. Some make beer and some are more interested in spirits.

I have an interest in a mixed grain whisky. My starting point will be a 35% corn, 35% rye, 15% oat, 15% barley mix with a 60/40 malt to unmalted split.

Now for me this means both an acid rest (sourmash) and a cooking phase as I will need to cook the corn and some of the rye.

I have just ordered a 205 litre stainless steel open top drum.

Now before you freak out let me explain. I wish to put a 150 litre copper liner inside that stainless drum to make a double boiler. The intent is to cook and mash the grain in the same container. OK I admit I also intend to do the strip run in the same container but that does not invalidate the principle of the mash/ferment idea.



So a 150 litre inner allows room to do a 20kg in 100 litre mash and leave plenty of space for fermentation.

I already have a keg based steam kettle to cope with the steam injection mashing, but am intending to gas fire the stainless drum to cook (and strip) the mash.

Why a 100 litre mash? It should yield 20 litres of low wines. Just right for a typical home size boiler for a spirit run.

The plan keeps evolving in details but this was the basic concept.

At first it was going to be electric, but I added gas heating and a vented shroud. The modified drum lid (vapour path to condenser) will be held in place with the origional drum clamp.

Even if you only want to cook/mash/ferment then an electric or gas double boiler might be just right for you. I did consider a stainless pot first but the drum clamp closure sealed the deal. There are also stainless 150 litre drums available if you wish to go a bit smaller.

Yes you can do RIMS/HERMS instead but the double boiler mash tun is an alternative.

And with clamp ring open top drums to hold the inner into the outer boiler it should be easy to achieve.

Might be of interest to some of you.

I don't know if I need to explain but the drums have a sealing ring on the lid.

Even if you only have a copper inner with no drains etc, just a drop in liner, the inner drum can be held into the stainless drum by trapping it between the drum and the lid.

Hmm. If you had added a couple of pumps, I would have had a feeling you were making a 200l braumeister.

My first thought, in electirc is far more controllable & cleaner & easier to setup than gas.

Not going to disagree with you.

In my situation though I am limited to 6 kW and can get more from gas.

Over night pre heat?

There is no doubt that if I had the wiring to support more than 6 kW that I would use it.

Nothing competes with the efficiency of the an electric immersion heater. If i had the choice I would put in a 10 mm square supply to my still room. Unfortunately for me that means adding a new phase which is too expensive. I even concidered a 10 kva deisel generator.

If you can do it with electric please go ahead. It is the best option.

Sounds like a big project, bigger than I've ever attempted, what's the idea with the inner copper? Is it a malt tube with holes in the bottom or is it solid and surrounded by water that's heated from the gas?

If it's a Bain Marie style with the inner pot being heated through the liquid from the bigger pot, be sure to have some kind of ventilation to prevent any pressure building up, you could even use oil instead of water.

I am trying to get my head around the double boiler thing here,but concede that it may help stop stuff scorching on heating up.
Is that the reason?

Robert.

Actually this was inspired by Swede's boiler.

It is a double boiler principally because it is going to be used to cook the grain. Anyone that has tried cooking corn or rye directly in a heated pot knows that it can be an issue.

It will be water in the jacket and it will NOT be a closed system. No bombs intended here, and just to be safe, it will also have a 0.5 Bar PSV installed.

The water jacket and insulation will help maintain temperature during the mash phase.
After fermentation I will actually be doing a strip run in the same container. So I will be both fermenting and stripping on the grain.

This is where Swede's mode of operation comes in, because once the water jacket starts boiling the steam produced will be directly injected into the boiler. This combination of a water jacketed boiler and steam injection does appear to have advantages. Won't know for sure until I have tried it myself.

Simplified drawing.

Am going to use a paella burner so the drain can go through the centre for ease of construction. that way the gas jets will be a little bit further away from the connector securing the drain into the stainless drum.

The flange on the copper liner is just trapped between the drum and the drum lid, and secured by the drum clamp.



Fitting the copper liner into the drum is easier if the drain is in the centre. I will fit a compression bulkhead connector into the stainless drum and fit the compression ring and nut onto the drain tube after the liner has been clamped in place.

Is fermenting in copper ok. I have a feeling it needs special consideration. If your washes are too acidic there would be a release of copper into the brew, not good.

Don't know for sure. Probably worth checking before you start.

You certainly shouldn't ever have hydrogen sulphide problems

You know something, I never even considered that.

Found this. Interesting reading.

Good find.

Best when bronzed. Hmm. Can we say then that this is similar to passivation in stainless?

@Myles: An exciting project with plenty of grunt.

I use gas. It works great. A diesel genset will get expensive to operate. And then there is the maintenance issue.

One question if I may - why a copper insert? Stainless would seem like a more practical choice.