diy thermowell

pcqypcqy said:

I'm thinking of using a threaded brass pipe as the basis of my thermowell as per the image below. I can then use a threaded end cap to seal it, and use 2 brass nuts with a rubber seal against the vessel wall (either mash tun or fermenter).

I have a similar set up on my HLT attached to a normal brass garden tap, seems to work pretty well.

I like this option because I can use the same pipe as the fitting through the vessel wall as well as the well itself. Also, I can disassemble the entire thing in seconds for a thorough clean before and after. It's also cheap, and the parts are readily available on the shelf at the hardware store.

I've seen other people suggest criping the end of a length of copper, stainless steel, or chromed toilet supply pipe, but you still have the issue of finding a fitting to go through the wall of the vesel. Doing it this way could avoid that problem by doing it in one piece.

Apart from having to keep the threads clean (which I can probably do with a toothbrush and PBW quite easily), are there any issues with this approach that I'm not seeing?

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Takuie said:

I do the same thing, only I use a 1/2 MNPT stainless nipple. The brass will oxidize, thusly protecting itself and help reduce any off flavors of metal or tin in your brew.

Yes, you could use brass. Copper would work as well. Stainless would be best. Brass could impart some odd flavors. Depends on the brass as well. There are some food quality brass parts out there, but for the price just toss a few more coins down and opt for stainless.

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pcqypcqy said:

I was thinking of at least using this in my mash tun to monitor temperatures to begin with. I'm having some issues with efficiency that I believe are temp related (beersmith giving me strike temps that are too high I think), so I want to check the temp on a few brews closely to monitor/adjust this. I already have brass fittings that my copper manifold connect to here, so it won't change what I'm doing drastically.

I wouldn't mind monitoring my ferment temps more closely as well. I use white buckets, and I'm using them once only at the moment because I had some issues with cross contamination of infection/odours, so I'm trying to rule this out. Also, white buckets are always useful (grain storage, animal feeds, compost toilet, etc). So any fermenter thermowell would have to be a dip tube in the lid.

I wasn't aware that brass could cause off flavours, I thought as it was an alloy of copper it was largely OK in brewing applications - feel free to correct me there?

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pcqypcqy said:

I was thinking of at least using this in my mash tun to monitor temperatures to begin with. I'm having some issues with efficiency that I believe are temp related (beersmith giving me strike temps that are too high I think), so I want to check the temp on a few brews closely to monitor/adjust this. I already have brass fittings that my copper manifold connect to here, so it won't change what I'm doing drastically.

I wouldn't mind monitoring my ferment temps more closely as well. I use white buckets, and I'm using them once only at the moment because I had some issues with cross contamination of infection/odours, so I'm trying to rule this out. Also, white buckets are always useful (grain storage, animal feeds, compost toilet, etc). So any fermenter thermowell would have to be a dip tube in the lid.

I wasn't aware that brass could cause off flavours, I thought as it was an alloy of copper it was largely OK in brewing applications - feel free to correct me there?

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pcqypcqy said:

Righto then, I will avoid brass in the fermenter.

Keep in mind that I'm in Australia and not the US, so everything here is 2 or 3 times more expensive. The only half decent thermowell I've seen here is a short little stainless thing that costs upwards of AUD$35. This doesn't even include the fitting to attach it to a wall or lid. I'll dig around a bit more to see if there's anything cheaper, or see if I can get some stainless threaded pipe and nuts.

Another thought I've had for the fermenter was to get some beer line, drill two holes in the lid of the bucket to fit the line snugly, then loop the line through so the open ends are outside of the bucket. Then simply dangle a probe down inside. I might need to wrap some thread tape around the line to ensure an airtight fit with the lid (this is what I do with my airlock in lieu of a grommet). But this is easily checked by pressing on the lid and seeing if the airlock bubbles.

I know that silicone/plastic doesn't conduct as well as metal, but I'm not after an instantaneous temp read for control, I just want to know what's going on in there so I can roughly calibrate my ferment chamber.

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acidrain said:

I've have a thermowell for my fermentor, and I've also just taped the probe to the side of the vessel. To be honest, taping to the side of the vessel actually works a little better. It seams that the cooling/heating system cycles more when the probe is deep inside the mass.
Just say'n...

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