Blow Offs

[Qs]

Seems almost every beer I make nowadays has a blow off. If I over pitch, if I under pitch, if I go to the exact measure suggested, if I use dry, if I have a starter, if I direct pitch. No matter what I still seem to get a blow off. I've been leaving more room in my FVs yet it still happens. Is there any cure for this, what are the general reasons for blow offs? I know its not the end of the world and the beer still usually turns out well but I'm fed up cleaning them and I worry they're throwing away my lovely hop aromas.

What other options are there if I can't fix it. What are the best blow off tube options? Where can I get even bigger fermenters?

[Shanna]

What temperature are you fermenting at? Do you have a way to regulate your temperature? I suspect your fermentation temperature is too high.

Shanna

[Qs]

I'm fermenting at 18/19C usually in a fridge with an STC controller. Usually using WLP001 or a dried equivalent. Right now I've a pale and an amber that both blew off last night, one with Mangraove Jacks M44 and the other with wlp001. The fridge is at 18.6C at the moment and has been since last night or so.  I have the probe stuck to the side of one of the FVs under a bit kitchen roll for insulation.

[Qs]

I meant to add earlier I've made blow off tubes by putting 3/8 line onto the airlocks or by just sticking it in the bung but have had them blow off too. I'd like to try some of that really wide tubing the americans use the fills the whole mouth of the carboy but I've never seen any on the Irish HBS. Anyone know where you can buy it?

[Shanna]

I'm fermenting at 18/19C usually in a fridge with an STC controller. Usually using WLP001 or a dried equivalent. Right now I've a pale and an amber that both blew off last night, one with Mangraove Jacks M44 and the other with wlp001. The fridge is at 18.6C at the moment and has been since last night or so.  I have the probe stuck to the side of one of the FVs under a bit kitchen roll for insulation.

If you have a plastic fermenter your temperatures will be under reported by a few degrees. I would recommend investing in a thermostat as the outside of the fermenter will insulate the liquid. If you have another fermenter half fill it with warm water & measure your temperature inside the ferment with a regular thermometer & compare it against the temperature outside using the temperature probe from the stc. This may not solve your blow off but it will give a better control over your fermentation temperature. I had the same setup.as you and the temperature was out by two degrees.

Shanna

[Qs]

Didn't realise they under report like that, I'll definitely give that a try once these beers are done and I have room in the fridge. Thanks.

[Shanna]

Didn't realise they under report like that, I'll definitely give that a try once these beers are done and I have room in the fridge. Thanks.

Yes I was surprised by it too. The first time I used a temperature controlled fridge I had a lot of phenols in my beer cause the temperature was higher than was being reported. Adding the thermowell sorted it out.

Shanna

[Pheeel]

What size batches and what size is your FV? I'd say your FV is too small for your batch size

[Qs]

I have about 18L I'd say in a 23L fermenter and then around 27L in what I'm guessing is about a 33L fermenter.

[Pheeel]

I've had blow offs with 5 in a 6 gallon carboy which is close enough to 18 and 23L. I have had no issues with 25L in the 33L plastic FV the STC probe strapped to the side with US 05. Sounds like this is a recent problem for you. What changed from before when you didn't get blow offs?

Would love to know what the M44 beer tasted like. I used it a few times and found the flavour to be off and the yeast was the most obvious culprit

[Ciaran]

Have you tried calibrating your stc sensor? Stick it in ice water and make sure he reading is correct.

[cruiscinlan]

Have you tried calibrating your stc sensor? Stick it in ice water and make sure he reading is correct.

Does the STC have a calibration function?

[Ciaran]

Not that I know of but if you can attach it to the side of a glass of I've you should be able to work out how close to 0 it can get? Just thinking it might be a few degrees under where it should.  Was also going to ask if you're maybe over pitching yeast

[krockett]

Interesting thread - I was wondering why I never had a blow off with beer (have done with cider). Have reached the conclusion that its my fermenter size. I use a 33 liter fermenter with 25 liter batches.

Also I've seen recently that if you overpitch you get much smaller krausen and a faster ferment.

[Frequent Sequence]

Function 4 is the calibration value on the stc1000. The easiest way I found to calibrate is with a pint of crushed ice topped up with water. Let it sit for two minutes and then take a reading. It should read 0. If you are reading low just add the difference. Ie. The ice water reads -1.5. Set F4 to +1.5

EDIT: This is a great guide on the stc1000 by LordEoin http://www.nationalhomebrewclub.ie/forum/index.php?topic=7491.0