Spike fermenters.

[awoitte]

By the time I'm ready to cold crash the psi has built up to around 10psi naturally.

... however if the psi was to drop to 0 and the fermentor is sealed you could crush it so be mindful when dropping temps with a sealed vessle.

By naturally do you mean you have co2 connected..?

Crushing a conical is one of my biggest fears. Is it only when going down in temperature that this may be a problem? How can a person operate to make sure this never happens?

 

[Blazinlow86]

By naturally do you mean you have co2 connected..?

Crushing a conical is one of my biggest fears. Is it only when going down in temperature that this may be a problem? How can a person operate to make sure this never happens?

Just ensure you always have positive pressure while dropping the temp down. Cheers

 

[Beardless]

By naturally do you mean you have co2 connected..?

Crushing a conical is one of my biggest fears. Is it only when going down in temperature that this may be a problem? How can a person operate to make sure this never happens?

Positive pressure is best for it. Otherwise, don’t have it sealed, but then you’ll get air pulling in or sanitizer suck-back (depending on the arrangement), so that isn’t actually an option.

 

[awoitte]

Just ensure you always have positive pressure while dropping the temp down. Cheers

So does that mean pressure lessens as temperature drops? And if so, at what rate? At first I thought: to have positive pressure I'd need to make sure there was enough co2 in there to not be completely absorbed by the liquid in addition to it changing due to pressure drop. I feel like its better to just have co2 feeding into it at a certain pressure. If that is the case then what is the minimum it should be to make sure my baby doesn't get crushed.

 

[Jag75]

I noticed it was about every other day I had to add some co2 to keep the psi @11. That was maintaining a temp of 55f .
It wasnt a lot of co2 just about 4-2 psi at a time

 

[Beardless]

So does that mean pressure lessens as temperature drops? And if so, at what rate? At first I thought: to have positive pressure I'd need to make sure there was enough co2 in there to not be completely absorbed by the liquid in addition to it changing due to pressure drop. I feel like its better to just have co2 feeding into it at a certain pressure. If that is the case then what is the minimum it should be to make sure my baby doesn't get crushed.

Someone can correct me if needed, but two things at play-
1. CO2 is more readily absorbed into the beer at lower temps
2. Volume shrinks a little when lowering temperature

So if you don’t have some excess CO2 in there, the shrinkage and absorption will tend to bring down headspace pressure. When I get to this point I typically hook up my regulator at 5-10 psi and leave it on until I package. At 35*F and 5 psi you’ll end up just over 2 volumes if you let it sit (same for 40*F at 7 psi), that’s my MO.

 

[eric19312]

Someone can correct me if needed, but two things at play-
1. CO2 is more readily absorbed into the beer at lower temps
2. Volume shrinks a little when lowering temperature

So if you don’t have some excess CO2 in there, the shrinkage and absorption will tend to bring down headspace pressure. When I get to this point I typically hook up my regulator at 5-10 psi and leave it on until I package. At 35*F and 5 psi you’ll end up just over 2 volumes if you let it sit (same for 40*F at 7 psi), that’s my MO.

Without checking a carb table I think you have it right.

The carb table shows beer temp on one axis and PSI on the other axis. If you hold PSI steady and chill the beer more CO2 gets absorbed and this shows as increase volumes. I used to think the main drop was from gas shrinkage due to the ideal gas law but after more evaluation I think the increasing solubility of CO2 in beer as temp drops is the greater impact.

 

[Beardless]

Without checking a carb table I think you have it right.

The carb table shows beer temp on one axis and PSI on the other axis. If you hold PSI steady and chill the beer more CO2 gets absorbed and this shows as increase volumes. I used to think the main drop was from gas shrinkage due to the ideal gas law but after more evaluation I think the increasing solubility of CO2 in beer as temp drops is the greater impact.

Someone previously corrected me about the same topic, so I’m regurgitating the information. My engineering background previously thought “shrinkage from temperature effect is the presiding factor”. Then someone brought up absorption and I went away with my tail between my legs- I hadn’t even considered that a factor.

 

[Blazinlow86]

So does that mean pressure lessens as temperature drops? And if so, at what rate? At first I thought: to have positive pressure I'd need to make sure there was enough co2 in there to not be completely absorbed by the liquid in addition to it changing due to pressure drop. I feel like its better to just have co2 feeding into it at a certain pressure. If that is the case then what is the minimum it should be to make sure my baby doesn't get crushed.

I think your overthinking this. If you seal the fermentor at room temperature then cold crash to freezing a negative pressure will build and possibly damage your vessel. This can be avoided by connecting a co2 tank at .0001psi or more while cold crashing or just charging to 10ish psi prior to cold crashing. Cheers

 

[Beardless]

I think your overthinking this. If you seal the fermentor at room temperature then cold crash to freezing a negative pressure will build and possibly damage your vessel. This can be avoided by connecting a co2 tank at .0001psi or more while cold crashing or just charging to 10ish psi prior to cold crashing. Cheers

Bingo- I shouldn’t have added more info than necessary, the idea is to prevent the pressure from going negative. In my original post I mentioned sucking in sanitizer or oxygen- by adding a source of co2, you allow that to go in instead. Remember whatever you set the regulator to is what pressure will be maintained. If you don’t actually want pressure, set it for 1 and leave it connected until terminal temperature (perhaps a little after).

 

[awoitte]

I think your overthinking this. If you seal the fermentor at room temperature then cold crash to freezing a negative pressure will build and possibly damage your vessel. This can be avoided by connecting a co2 tank at .0001psi or more while cold crashing or just charging to 10ish psi prior to cold crashing. Cheers

Thanks, and you're right, the answer was pretty simple/clear. I think my brain has gotten a little overwhelmed while reading the other 29 page Spike thread over the last 3 days =)

 

[NewJersey]

I JUST bought flex + a few minutes ago.
Glad I wandered over here and opened this bad boy up.
Thanks, guys

 

[awoitte]

Brewers hardware yeast harvester helps out with both trub dump and yeast harvest immensely.

Without the harvest, I did lose more beer than I should have. With the harvester, on the first attempt it worked great.

For someone who's just looking into harvesting yeast, is the top or the bottom the good stuff?