Only 11c in the brewfridge...

[grooves]

On Saturday morning I brewed a Golden Ale - it should come out at 4% with just a single charge of Goldings at the start of the boil, it's a nice simple beer brewed with US-05. However thanks to this cold snap the brew fridge is now down to 11c! I had intended to maintain around 19c. It is down from 1.040 to 1.030 so something is going on, but 11c is far outside of the quoted range for 05. I'll continue to monitor it and it should warm up a bit over the next days, but do you think the beer will suffer any ill effects?

 

[Chippy_Tea]

How are you controlling the brew fridge?

 

[fury_tea]

On Saturday morning I brewed a Golden Ale - it should come out at 4% with just a single charge of Goldings at the start of the boil, it's a nice simple beer brewed with US-05. However thanks to this cold snap the brew fridge is now down to 11c! I had intended to maintain around 19c. It is down from 1.040 to 1.030 so something is going on, but 11c is far outside of the quoted range for 05. I'll continue to monitor it and it should warm up a bit over the next days, but do you think the beer will suffer any ill effects?

Cold temps can knock the yeast out of suspension. Throw some lager yeast in there and call it a Goldings lager?

How has the brew fridge got that cold? Have you not got a heater in there? I don't know how much space you have but I've managed to keep a stable 38c (for kveik) in mine using a small heater and a 12L fermenter filled with hot tap water (periodically refilled) in the top of my upright fridge.
I'm sure you could use this technique to raise the temp in your brew fridge if you have space?

 

[grooves]

STC controller connected to fridge and a tube heater, with the probe in a thermowell in the middle of a SS conical. Looks like the tube heater isn't up to it. The shed is -1c despite having mostly insulated walls. I'm surprised the thermal mass of the beer and the fridge insulation hasn't been enough - I pitched at around 21c do to some problems when cooling the wort.

 

[Chippy_Tea]

I wonder if the tube may be faulty as i know many members use a 12 inch - 40w heat tubes and non have reported low temperature problems.

 

[grooves]

Yeah - I'm on my second one - but it was hot just now when I moved its position to try to help.

Perhaps fortunately I'm growing up some WLP835 from a frozen sample for the next brew, so I may have to use it earlier than intended if this fermentation stalls...

 

[Neil Whittaker]

How big is the brew fridge? It crossed my mind that more surface area the fridge has, the less efficient it will be. Thus, I went for a under the counter one.

Does the tube heater have a thermostat built in? Could have been accidently turn down.

My under the counter fridge is in the garage, it hit zero in there, but the fridge held 20c, with the 40W tube heater.

 

[Clint]

Daft question....is the probe definitely in the fridge?
A couple of times I've been out faffing round with my brew fridge and left the probe out...

 

[Benfleet Brewery]

As Mentioned above, unless the fridge is too large, it seems like there’s a problem with the heater. My second brew fridge is struggling at the moment but it only has a cheap 7w reptile heat mat in there and is still keeping at around 17.5-18 degrees.

 

[Neil Whittaker]

I was worried that my modification would be too extreme and mess up the fridge ability to hold heat.

 

[Chippy_Tea]

Yeah - I'm on my second one - but it was hot just now when I moved its position to try to help.

If you are using a shelf like the one below does it allow enough heat to rise some members cut slots to allow this.

 

[LeeH]

As CT says ^^^^

Like that, the heater can go out on over-temp as a lot of the heat gets trapped and builds up. Even if your STC is calling for heat the tube is off/cooling without you even knowing.

 

[Justin Dean]

How big is the brew fridge? It crossed my mind that more surface area the fridge has, the less efficient it will be. Thus, I went for a under the counter one.

Does the tube heater have a thermostat built in? Could have been accidentally turn down.

My under the counter fridge is in the garage, it hit zero in there, but the fridge held 20c, with the 40W tube heater.

I have two larder fridges, can get down to 2c and up to 38c mate , ceramic bulb

 

[Clint]

If you are using a shelf like the one below does it allow enough heat to rise some members cut slots to allow this.

It's like Yellowstone national park...

 

[Chippy_Tea]

It's like Yellowstone national park...

I know i am going to regret asking the moment i click "post reply"

What do you mean Clint?

 

[Clint]

Underneath Yellowstone park is a super volcano....when it goes pop...all of North America is f****!

 

[Bill_g]

It's always difficult to work these things out on the fly during fermentation but in this situation the quickest fix would be to add some emergency heaters. These could be two or three e.g. 60W incandescent bulbs wired up to the STC1000 and placed in the bottom of the fridge. A brew belt heater would be another option which could easily be added without too much disruption of the fermenter.
Once fermentation is complete than you can test the system to see what's going on. The tube heater sounds suspect, or as already suggested is cutting out due to its own thermostat being set too low (assuming it has one).
A useful test would be to sit the heater in your usual brew volume of water in the fermenter in its normal fridge set up. Set the STC to a high temperature & measure the temperature rise of the water. This will give you a rate of rise of temperature and a final stable temperature. The difference between this temperature and the external shed ambient will tell you the maximum capability of the heater and fridge insulation system. For example: shed ambient = +10C, final stable water temp = +25C. Difference = 15C. So the shed ambient temperature would need to be >+3C to hit a target fermentation temperature of +18C.
It's difficult in practice to have too much heater capacity as long as you have a thermostatic temperature controller. Commercial brewing heaters tend to be very under powered because often they are used without thermostatic control & their purpose is to raise the temp of the fermenter by just a few degrees.

 

[grooves]

If you are using a shelf like the one below does it allow enough heat to rise some members cut slots to allow this.

I think this is what it was - it's a new shelf I built recently and I didn't cut any ventilation holes. I've moved the tube heater on top of the shelf and the beer was 16c this morning and is now 17c and down to 1.023 from 1.040 OG - so looks like it will be ok.

I'm still surprised that the beer got as low as it did in such a short time given the fridge is insulated. It's a tall fridge - it has to be to fit the 5gal SS brewtech conical on top of the bump where the compressor is located.

Thanks for the suggestions. I'll keep eye on it as this is the first time I've had a problem.