Placing of Inkbird Temperature Probe

[Col Robinson]

A question for Inkbird users. I’ve seen a video, from Malt Miller if memory serves me right, in which the guy recommends putting the temperature probe in a jar full of steriliser solution instead of taping it to the outside of the fermentation bin. The jar then sits in the fridge next to the fermie bin.
Does anyone use this method? I would have thought that, because there is much less liquid in the jar than the fermie bin, the probe would be telling the inkbird to alternately heat up or cool down before the wort reached the desired temperature? I mean, a jar full of liquid will heat up/cool down much more rapidly than a bin containing 19 litres. Or am I missing something here?

[McMullan]

The best option is to feed it into a thermowell placed in the wort to measure the actual temperature. Next best option is to tape it to the FV wall and cover with a little insulation. I wouldn't put the probe directly in liquid, especially something like sanitiser. The only time I'd do what you're suggesting (probe in a small bottle) is to stabilise the temperature controller, say, in a serving fridge or keezer. In that case glycerol is the best thing to use, rather than sanitiser.

[Jocky]

I put mine on the outside of the fermenter with some insulation over it to begin with. The reason is because I’m trying to control the fermentation temperature. If you have the probe in a jar of water then your chiller will not react to run away fermentations, which can be a problem for bigger beers.

Towards the end of fermentation I’ll take off the insulation so I don’t add to much heat/cooling to the fermenter.

[nickjdavis]

I mean, a jar full of liquid will heat up/cool down much more rapidly than a bin containing 19 litres. Or am I missing something here?

No...you are not missing anything.

As previously advised, a Thermowell is the best option followed by taping the probe to the wall of the FV and insulating it with something like bubble wrap.

[guypettigrew]

Malt Miller does a range of thermowells. What's your fermenter made of?

Guy

[Top Cat]

FWIW I do the same as Jocky. I’ve taped a patch of insulation material, on to the bin half way up, to form a pouch, the stuff you put behind room radiators to reflect the heat.
I simply slide the sensor in, and remove when I take the bin out of the fridge.
I do have a stainless bin that being a better conductor of heat than plastic, gives a more accurate reading of what’s going on inside.
From reading previous posts when fermentation is vigorous it could be warmer inside the vessel than where I’ve got it positioned. On a couple of occasions, after sterilising, and when fermentation is going like the clappers, I’ve dropped the sensor in the beer from the hole in the lid to see what difference I get. It’s barely 0.5c.
Good enough for me!

[Cobnut]

I recently bought a SS conical (from Brewbuilder btw) and specced a thermowell as part of the order.

I also use a Tilt hydrometer which reports wort temperature.

I brewed a Kveik Pale Ale yesterday which called for a high pitching temperature of almost 40C which showed up a significant difference between the STC-100 probe in the thermowell and the Tilt in the wort of around 2C.

At more normal ale/lager temperatures, I've noticed a difference of a degree or so, but this surprised me.

[f00b4r]

If attaching to the side, I find ratchet straps are better than tape to hold the insulated pouch to the fermenter.

[Silver_Is_Money]

As previously advised, a Thermowell is the best option followed by taping the probe to the wall of the FV and insulating it with something like bubble wrap.

Many intuitively presume that the internal temperature will likely prove to be noticeably higher than the surface temperature, but due to the churning of the Wort by the yeast, actual dual measurements of internal and surface temperature are much closer than intuitively envisioned. Very little difference is measured if insulation is placed over the surface probe.

[McMullan]

As previously advised, a Thermowell is the best option followed by taping the probe to the wall of the FV and insulating it with something like bubble wrap.

Many intuitively presume that the internal temperature will likely prove to be noticeably higher than the surface temperature, but due to the churning of the Wort by the yeast, actual dual measurements of internal and surface temperature are much closer than intuitively envisioned. Very little difference is measured if insulation is placed over the surface probe.

That assumption is based on an overly simplistic model that all yeast cells (of the same strain) are doing exactly the same thing during active fermentation, when most heat evolves, and all FVs are the same. This is simply not the case. In reality what we have during active fermentation is a heterogeneous environment that doesn't necessarily conform to convenient generalisations and averages. Welcome to biology! An 'ideology' to some. It depends on what the FV is made from (glass, type of plastic, stainless, etc.) and how thick its walls are. And which yeast strain is used. Some strains ferment at a higher rate, for instance, with a higher rate of exothermic reaction going on therefore producing more heat, unless laws of physics are being broken. So, the best advice really is, if it's an option, use a thermowell to measure actual wort temperature. If not, fit an insulated temperature probe to the external wall of the FV. If neither's an option, set the temperature 3-4℃ below the desired temperature during active fermentation.

[D215Aquitania]

I'm using an Inkbird strapped to the side of the (plastic) fermenter (under a chunk of foam sponge) & a Tilt inside it. With the Inkbird set to 18C the Tilt is reporting within +/- 1/2C of that. There's a bit of rounding going on (the Tilt works to the nearest 1F & then converts to C iirc) but that's close enough for me.

[Silver_Is_Money]

I'm using an Inkbird strapped to the side of the (plastic) fermenter (under a chunk of foam sponge) & a Tilt inside it. With the Inkbird set to 18C the Tilt is reporting within +/- 1/2C of that. There's a bit of rounding going on (the Tilt works to the nearest 1F & then converts to C iirc) but that's close enough for me.

Thank you! Real science such as this always trumps intuition. You have confirmed what many have also directly observed and reported in the past, I.E., that there isn't a difference that matters between internal and insulated surface temperature measure.

[McMullan]

I'm using an Inkbird strapped to the side of the (plastic) fermenter (under a chunk of foam sponge) & a Tilt inside it. With the Inkbird set to 18C the Tilt is reporting within +/- 1/2C of that. There's a bit of rounding going on (the Tilt works to the nearest 1F & then converts to C iirc) but that's close enough for me.

In what context exactly? During active fermentation? Every time? How do you actually record the Inkbird output, a quick look-see occasionally? Using a Tilt and Inkbird calibrated under the same conditions then confirmed to be ‘comparable’? Otherwise there is a chance both outputs are wrong to varying degrees and your assumption your fermentations are within +/- 0.5℃ of your desired set temperature is just that, an assumption. It could be way out. You could be biased by superstitious beliefs and cultural expectations of what you’re supposed to observe, according to home-brew lore. Not exactly ‘real science’ but ‘close enough’ for you. It’s fine. It’s only home brew, right?

[guypettigrew]

I'm using an Inkbird strapped to the side of the (plastic) fermenter (under a chunk of foam sponge) & a Tilt inside it. With the Inkbird set to 18C the Tilt is reporting within +/- 1/2C of that. There's a bit of rounding going on (the Tilt works to the nearest 1F & then converts to C iirc) but that's close enough for me.

What is your Inkbird doing? Is it controlling a heater/cooler?

The other thing worth noting is Tilts, in my experience, always move to the side of whatever vessel they are in. So your Tilt and Inkbird thermostat might be in almost the same place!

Guy

[McMullan]

trumps intuition