Grainfather conical fermenter Vs fridge?

[Stu's Brews]

I might investigate emptying the glycol and putting a fresh batch in, see if that helps.

Might be worth checking the temperature of the glycol too if that is possible.

 

[Modena]

There is a design flaw in the GF conical that when combined with the weird water density behaviour causes this issue.
The water density tipping point is at 4C, below which, its density drops.
So what happens is that the cooling sleeve creates a very cold wort layer at the top, inhibiting the natural convection to flow to the bottom of the fermentor, where the temperature probe is located
This causes the chiller to run indefinitely

 

[Modena]

Is it actually going back up above 6.4degC though? That's when the pump should kick back in to cool it down again. Doesn't look like it from the graph you shared.

The only other reasons why it wouldn't maintain the target temperature is that the coolant temperature (the glycol in your case) is too high or there is a fault.

I can only speak from experience but mine works flawlessly (within the limitations of not having a glycol chiller). In the depths of winter I've had mine down as low as 1degC as once it has cooled down it never rises back up again.

I believe the reason Grainfather don't recommend cooling below 4-6degC is because the cooling jacket only covers a portion of the fermenter so you can end up with uneven temperature distributions.

Yes Stu,
The temperature rises above the histeresis l, when the pump kicks back in to cool the wort, but the reading keeps rising.

 

[Stu's Brews]

Yes Stu,
The temperature rises above the histeresis l, when the pump kicks back in to cool the wort, but the reading keeps rising.

I'll have to take your word for it as it doesn't look like it does on the graph you shared. To me it looks like as soon as it rises above the hysteresis value you increase the target temperature. There will be a lag between the hysteresis temperature being exceeded and the cooling taking effect again so you may just need to give it more time.

Assuming it is failing to cool correctly then:

Have you checked the temperature of the glycol?

Is the coolant definitely flowing through the jacket / can you hear the pump running when it is cooling?

Do you get the same behaviour on both of your fermenters?

Have you tried contacting Grainfather themselves or the store you purchased from to see if they can help investigate a potential fault?

 

[Stu's Brews]

There is a design flaw in the GF conical that when combined with the weird water density behaviour causes this issue.
The water density tipping point is at 4C, below which, its density drops.
So what happens is that the cooling sleeve creates a very cold wort layer at the top, inhibiting the natural convection to flow to the bottom of the fermentor, where the temperature probe is located
This causes the chiller to run indefinitely

This is correct (the physics at least, not sure whether it's fair to call it a design flaw) and is why they state not to set the temperature below 4-6degC.

I'm fairly confident that is a separate thing to the issue you've raised about it not maintaing a temperature of 6degC though.

 

[Modena]

I'll have to take your word for it as it doesn't look like it does on the graph you shared. To me it looks like as soon as it rises above the hysteresis value you increase the target temperature. There will be a lag between the hysteresis temperature being exceeded and the cooling taking effect again.

Assuming it is failing to cool correctly then:

Have you checked the temperature of the glycol?

Is the coolant definitely flowing through the jacket / can you hear the pump running when it is cooling?

Do you get the same behaviour on both of your fermenters?

Have you tried contacting Grainfather themselves or the store you purchased from to see if they can help investigate a potential fault?

Glycol temp and chiller settings are according to the manual recommendation.
Coolant is flowing well. There's water condensation on the outside and sometimes the condensation freezes onto the quick disconnect.
Same issue on both fermenters.
I have not contacted Grainfather support.

 

[Stu's Brews]

I have not contacted Grainfather support.

I'd suggest that as a next step then as I'm out of ideas as to what might be causing whatever problem you are having.

 

[Deadhead]

Yeah, contact GF support as they are pretty helpful.
I cold crash to 4C and it seems to stay there just fine.

 

[Dilettante Brewing]

My GF conical + glycol chiller has been absolutely fine.

 

[Modena]

My GF conical + glycol chiller has been absolutely fine.

What's the coldest temperature you can keep at?

 

[Dilettante Brewing]

What's the coldest temperature you can keep at?

4degC

 

[MashBag]

I am now contemplating getting a grainfather conical fermenter with digital controller but are they actually worth the expense or is it just marketing hype?
Thanks

No.

 

[MashBag]

Imagine when you're halfway fermenting a lager(because it's so easy to do in these), and run out of beer, and you feel yourself ashamed to go to the supermarket to buy beer...

With the money you save, you can buy a lot of beer and have some change for an ice cream

 

[Birdsnestbrewery]

No.

Mine was :)

 

[Agentgonzo]

No.

Mine was :)

value is entirely subjective.

 

[MashBag]

I was going to say that

 

[Modena]

Update after about a year. I reached out to Grainfather and they couldn't help.
The fermenter keeps being an issue as you can see below. This is a better graph than the previous one I had shared. I just can't keep the beer cooling at 6C because it will eventually start rising.

 

[MashBag]

#1. Run this with water only not beer.
Measure the temp at different heights in the fermenter.

Is this a 'readings' thing or and 'actual' thing.

#2. Repeat the process with salty water 5% instead of glycol.


I still have a few ideas depending on what you find. My favorite option being thermal lamination and the lack of movement between the cooling effect and the sensor.

 

[Modena]

#1. Run this with water only not beer.
Measure the temp at different heights in the fermenter.

Is this a 'readings' thing or and 'actual' thing.

#2. Repeat the process with salty water 5% instead of glycol.


I still have a few ideas depending on what you find. My favorite option being thermal lamination and the lack of movement between the cooling effect and the sensor.

Hi Mash,
Yes, thermal lamination is the issue, as I wrote earlier in 2023.
Grainfather acknowledges this limitation on their manual, stating that the user shouldn't cool it lower than 6C. But even at 6C, the issue keeps happening.

 

[MashBag]

In that case #2

Could you also consider a mod of some kind. Create gentle movement (magnet stirrer springs to mind) or relocate the sensor?