Is a Blow-off Tube Actually Necessary?

[sifty]

After an explosive Russian Imperial Stout I always use a blow off tube. Made a hell of a mess. Clogged the airlock then blew out the sides of the lid. Even the blow off tube I then rigged into a flask was messy, this is a screenshot of an entertaining video...

 

[aolcot]

I always use a blow off tube ever since a few years ago I had a 8%+ black IIPA blow the cap + airlock clean off and made a mess everywhere. Couple with the fact that prior to that i've had fermentations push all the star san out the airlock as well I made the switch to a tube and not looked back..

 

[foxbat]

I use a blow-off tube because an airlock wouldn't fit in the fridge plus I like to direct the CO2 through the keg I'll be using for packaging to purge it for free.

I've never had a primary fermentation escape the fermenter possibly because it has a large surface area to height ratio. Those tall buckets look particularly vulnerable to me. However it happens all the time with my starters so I'll be buying some Brupaks Antifoam to use in all future starters. Maybe that's the answer to all of you that are having krausen issues?

 

[Agentgonzo]

I have a similar proportioned fermenter (8 gallon for a 5 gallon brew). I've never used a blow off and I've never needed to. And I've done some big (1.090) beers in there and some beers where it is fermenting so actively that there is no gap between airlock bubbles. I've never had it come out of the airlock

 

[jof]

I very rarely have a problem with my fermenter sat in the utility room, but I could imagine if yours is in a temperature controlled fridge that's set for optimum yeast growth that you might require said blow off tube.

Anyone tried dialing down the temperature a few degrees to reduce the risk? After all most of us leave the beer for 2 weeks these days & don't have commercial pressure to maximise throughput

 

[Donegal john]

I very rarely have a problem with my fermenter sat in the utility room, but I could imagine if yours is in a temperature controlled fridge that's set for optimum yeast growth that you might require said blow off tube.

Anyone tried dialing down the temperature a few degrees to reduce the risk? After all most of us leave the beer for 2 weeks these days & don't have commercial pressure to maximise throughput

2 weeks ? Rarely that long. For me anyway.

 

[Erik The Anglophile]

I have looked into the imperial/American standard system. Tbh it makes sense your science guys use metric while doing research, the imperial system with all the 3/16 and 5/8 and quarters and what not is just a hot mess inviting for errors and missunderstandings.

 

[Agentgonzo]

2 weeks ? Rarely that long. For me anyway.

I used to ferment it out for 7-10 days, but recently I have been going 2 weeks (or longer if I'm busy). I bottle condition all of my beers and I've noticed a huge reduction in the amount of sediment in the bottom of the bottle if I leave it in the fermenter for at least 2 weeks.

With a 10 day ferment previously, the airlock would have stopped any noticeable activity, but when I racked into bottles it was still hazy. After conditioning, I would end up with a few mm of yeast sediment in the bottom of the bottle, which is too much (the last few tablespoons would be either super-turbid or discarded).

With a 14 day ferment (I don't cold-crash, this just sits in the utility room at 20°), the airlock still has no activity, but when I rack the beer, it is crystal clear. There is still suspended yeast that allows it to carbonate in the bottle, but this time, I get less than half a mm of sediment in the bottom of the bottle and I can normally get all but the last few mm out of the bottle without any sediment. I get more (and clearer) beer by leaving it an extra 4 days in the fermenter.

 

[Agentgonzo]

I have looked into the imperial/American standard system. Tbh it makes sense your science guys use metric while doing research, the imperial system with all the 3/16 and 5/8 and quarters and what not is just a hot mess inviting for errors and missunderstandings.

TBH, I've always thought these pitch rate calculations are overthinking it for homebrew. I do one sachet per brew (2 if doing a high gravity beer). If it's slightly under or over the 'perfect' pitch rate, then it'll just ferment out a bit slower or faster. I honestly don't think anyone would be able to tell the difference in the finished beer

 

[Donegal john]

I used to ferment it out for 7-10 days, but recently I have been going 2 weeks (or longer if I'm busy). I bottle condition all of my beers and I've noticed a huge reduction in the amount of sediment in the bottom of the bottle if I leave it in the fermenter for at least 2 weeks.

With a 10 day ferment previously, the airlock would have stopped any noticeable activity, but when I racked into bottles it was still hazy. After conditioning, I would end up with a few mm of yeast sediment in the bottom of the bottle, which is too much (the last few tablespoons would be either super-turbid or discarded).

With a 14 day ferment (I don't cold-crash, this just sits in the utility room at 20°), the airlock still has no activity, but when I rack the beer, it is crystal clear. There is still suspended yeast that allows it to carbonate in the bottle, but this time, I get less than half a mm of sediment in the bottom of the bottle and I can normally get all but the last few mm out of the bottle without any sediment. I get more (and clearer) beer by leaving it an extra 4 days in the fermenter.

I don’t bottle I keg most of my beers. So a cold crash drops out most and my conical makes sure all the turb stays where it should. 10 days or 7 with kveik.

 

[Donegal john]

TBH, I've always thought these pitch rate calculations are overthinking it for homebrew. I do one sachet per brew (2 if doing a high gravity beer). If it's slightly under or over the 'perfect' pitch rate, then it'll just ferment out a bit slower or faster. I honestly don't think anyone would be able to tell the difference in the finished beer

I always do 1 packet but normally add some yeast nuitrent and a blast of pure oxygen before pitching. Never an issue.

 

[Madhouse]

I use a blow off tube just because it's easier - both to fit in the ferm fridge and on the rare occasion I run out of headspace, to clean up the resulting yeasty mess.

 

[Agentgonzo]

Blow off tubes are an excellent way of doing an easy top-cropping of fresh healthy yeast if you need it

 

[Jim Brewster]

Only had overspill once, when I did a high gravity beer around 8% otherwise been fine. I use dry yeast.

I've seen them used in microbreweries with SS fermenters with a huge amount of CO2 coming out

 

[Erik The Anglophile]

TBH, I've always thought these pitch rate calculations are overthinking it for homebrew. I do one sachet per brew (2 if doing a high gravity beer). If it's slightly under or over the 'perfect' pitch rate, then it'll just ferment out a bit slower or faster. I honestly don't think anyone would be able to tell the difference in the finished beer

I have done that approach as well, I have looked at the brewers friend calculator, and assuming the 2billion cells/gram assumption is a bit optimistic and the 1billion of brewersfriend is a wee bit over-conservative, we land at 1.5 billion cells/gram as a middle of the road. This calculated at 0.75 billion cells per liter of wort.
For my coming brews wich will be 20L in the FV and about 045-052 OG, this gets me in the desired pitch rate +/- 20 billion cells or so, a bit more of an overpitch for stouts and some others I tend to do slightly smaller batches of, in relation to the 170 or so billion cells needed, those few that differ will most likely not do any real difference.
Tl:dr if you brew normal strenght beer in batches of about 15-20L, chuck in a pack of dry yeast and trust them to do their thing.

 

[Erik The Anglophile]

To be on topic. If you don't notice any problems with krausen trying to escape, you likely Will be fine with an airlock.

 

[DavidDetroit]

After an explosive Russian Imperial Stout

Wow.
What percentage of headspace were you dealing with on that batch?

 

[DavidDetroit]

I always use a blow off tube ever since

I'm curious as to the amount of headspace you leave for a brew?

 

[fgoulding]

For my plastic spiedel fermentor, I always use a blow-off tube because there isn’t a lot of room at the top of my fermentation fridge.

I also have Fermzilla All Rounder’s on which I just use a spunding valve alone. But I’ve heard that some people add a blow-off tube to the valve and then into a jar of starsan in order to see fermentation activity….

 

[sifty]

Wow.
What percentage of headspace were you dealing with on that batch?

Had to look at my notes.
A 25 litre batch in a Mangrove Jacks s/s fermenter, so around 5.2 litres headspace, = approx 16-18%...?
After fermentation I'd lost a couple of litres, mopped that up from bottom of the brew fridge. Was fascinating to watch, a plug of foam would travel down the tube, pressure building behind it, so when the foam pushed out a huge burst of bubbles erupted...