Interesting temperature differences

[Polcho]

So I finally have the RAPT Pill connected to the Grainfather, and yes, I can access both from a mile away, I went to the allotment to check the pollytunnels after that wind.

The temperatures are very differnt.

The RAPT is showing around 1 3/4 of a degree difference from the Grainfather fermenter.

I like to ferment at a bit on the low side, nothing much, but I have the grainfather set at 22, and the RAPT is showing 20.1

Thats quite a bit of difference.

I did have the fermentar apart when I fitted the new controller, just to see what was inside.

The heater is a probe looking thing set in the airspace between the cone and the outer case, so it's heating the bottom really, whereas the RAPT is actually in the must.

Anyway, I've decided to pop it up a degree.

 

[Polcho]

Well, it's next morning now.

The difference in temperature readings got as far apart as 6.2 deg, at around 23.30 yesterday. That's quite surprising!

Now its about 1.7 deg difference.

I would expect a degree or so, just from the fact that heat rises, but 6 deg, is still a lot.

I'm guessing it will warm up on top once the fermentation really gets going

 

[peterpiper]

I guess the larger differences, were during cold weather. And that the air heater, is probably designed to work well, in warm climates.

Static air, is a really poor conductor of heat, while moving air, is fairly good.
My garage setup (not GF), for doing lagers during cold weather spells (0 - 5°C), can have be 10°C lower around top, than near heater.
Don't have a GF fermenter, so don't know if heater will give good air convection, around most of the fermenter. Any un heated areas, will be colder, the cooler the ambient air, and the poorer the insulation.

it seems GF heater is only 30W. In a cold room, with poor overall insulation, 30W might be insufficient to maintain temperature. Extra insulation, old duvet or PU foam outer box (eg old fridge), could help here.

Seems a shame the GF glycol cooler, can't also do heating. That would be able to keep the must warm when operated in cold rooms, and be much better suited to use in UK.

 

[MashBag]

Chinese priverb: man with two watches never no time.

Pick one. Calibrate it

 

[Polcho]

Chinese priverb: man with two watches never no time.

Pick one. Calibrate it

I'm begining to think along those lines myself, but it's been an eye opener, and I wouldn't have increased the temperature.

It's two deg apart now, and for once, it started fermenting by next moring.

Anyway, it's fun watching the gravity.

 

[foxy]

I'm begining to think along those lines myself, but it's been an eye opener, and I wouldn't have increased the temperature.

It's two deg apart now, and for once, it started fermenting by next moring.

Anyway, it's fun watching the gravity.

I found the same thing. It’s only when heating, you can set the heating temperature but you can’t control the temperature the yeasts exothermic energy.
Mine went up almost 11 degrees over the set temperature. First thought was the heating controller had carked it, but realised it was the yeast. I have read in a BYO article about the very same thing but this was the first time experiencing it.
I will add the thermentor was well insulated so the heat coming from the fermenting wort had no where to go.