Hi All, just changing everything over to Eva Barrier and Duotight. I am using fermentation gas to purge the dry hop and serving kegs, then gas out of serving keg to a jar of sanitizer for blowoff. Will the 4mm tubing be big enough for moderate fermenting yeasts? I put some gas in the fermenting keg to check all the fittings for leaks. The bubbles coming out of the blowoff were quite small. About to brew a 1.063 IPA with Apex San Diego yeast. What do you think?
4mm Eva Barrier for blow off tube?
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I switched every beer, gas and water line in my brewery over to EVABarrier in 2019, and it did necessitate a couple of strategic adaptations to prevent random messes. One of which was to put a sealed PET catch bottle between my carboys and the pair of kegs (outside the fridges) that get purged by the fermentation gases. You can see at the left side the catch bottle has some blown-off krausen in it, and the next day the batch on the right had the same. Meanwhile the kegs were getting purged nicely. The tubes between the carboys and the catch bottle are 7/16" ID.
So...I recommend using something similar, because expecting blow-off to go through 4mm ID tubing for any distance might lead to a bigly mess
Cheers!
So...I recommend using something similar, because expecting blow-off to go through 4mm ID tubing for any distance might lead to a bigly mess
Cheers!
@day_trippr what size is that line coming out of your trap? The trap is to prevent the clog @whoaru99 is mentioning?
I should mention that I am fermenting a 3.5 gallon batch in a 5 gallon keg. Do you think I might have enough headspace?
I changed all the tubing last night. The brew kettle is running now...
I should mention that I am fermenting a 3.5 gallon batch in a 5 gallon keg. Do you think I might have enough headspace?
I changed all the tubing last night. The brew kettle is running now...
I've never used 4mm EVABarrier tubing when fermenting in a corny keg before, nor would I recommend it. I have used 5/16id. I left between a half gallon and one gallon of headspace in the keg, and used a krausen catcher similar in design to what @day_trippr has. In the end that worked, but I probably won't even go that route again due to the potential of disaster, (maybe I just got lucky). In my case also added two kegs beyond the krausen catcher, and a blow off 64oz plastic pitcher at the end of the line. Several times all evidence of blow off stopped abruptly for 20-30 seconds or so, followed by intense blowoff for a few seconds, as the clog pushed through and released a torrent of gas, and blow off water splashing out of the pitcher. I can only imagine what would have happened with 4mm EVABarrier.
Tubing between carboys and PET bottle is 7/16" ID. And, yes, it's a "krausen catcher" intended to avoid clogging the EVABarrier tubing. I've used this rig on every batch since 2019 with only excellent results.
No idea if your scheme would be unlikely to clog, but I wouldn't count on it...
Cheers!
No idea if your scheme would be unlikely to clog, but I wouldn't count on it...
Cheers!
ihavenonickname
Well-Known Member
If you are fermenting in kegs and using a gas post quick disconnect as your gas out that little poppet becomes you most constricted point that will clog first. The 4mm tube after that won’t matter.
But yes that poppet will clog easily. I make sure to have enough head space and adding a little pressure helps keep krausen down.
But yes that poppet will clog easily. I make sure to have enough head space and adding a little pressure helps keep krausen down.
I have been fermenting similar batches in kegs for awhile without krausen coming out. I had clear 5/16" vinyl tubing so I should have seen it. Well, this batch is going to go with the 4mm since I trashed all the old tubing. Hopefully any mess will be confined to the chest freezer. I think I will look into making a catch can or at least the 6.5mm Evabarrier.
Beerstein
Well-Known Member
I use eva barrier all the time for blow off tubes. Works fine for me. Never had a problem, even with aggressive ferments.
Whisky River
Well-Known Member
If you are fermenting in a sealed corny keg using a ball lock post with the poppet valve installed and a 4mm tube for blow off, the risk of a clogged poppet, blow off tube, PRV is a lot greater than just having a big mess to clean up. Please be aware that an over pressurized keg can explode with enough force to be extremely dangerous to anyone living in your house.
Climb
Well-Known Member
For blow off tubes, you can’t go wrong with a larger ID hose. That said, I use the 5 mm ID EVA tubing as a blow off hose and have not had a problem. However, I ferment 10 to 12 gallon batches in a 15.5 gallon Sanke keg (half barrel). So my fermenter is never more than 77% full at pitch. If you are doing 3.5 gallon batches in a 5 gallon keg, your 70% full at pitch. I think you will be fine.
I had BrewHardware make a couple of 1/2" stainless blow-offs for me. Part of my project to keep O2 away from the cold side. Sticks out of a rubber stopper on top of the carboy and runs down to a mason jar filled w/ star san solution. Easy to position, easy to clean, robust, and effectively zero permeation.
Brushwood Brewing
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I do it successfully. I ferment 4.0 - 4.5 gallons in a 5 gallon corney keg, with 4mm ID EVAbarrier on the gas QD for a blowoff. I haven't had any issues.
Thanks @Climb and @Brushwood Brewing for the hope, maybe I will get lucky too! First time using Apex San Diego yeast. It is 22 hours post pitch and first signs of activity. I really hate slow starting yeast... I was worried I had a leak
4mm EVA will work every day up until the day you have a little more beer and less headroom along with an active yeast. Then forget about it.
Please have a plan B for where the pressure buildup will release. Pop a stopper out of a carboy, maybe have a PRV of some kind...
Please have a plan B for where the pressure buildup will release. Pop a stopper out of a carboy, maybe have a PRV of some kind...
Brushwood Brewing
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If he's fermenting in a keg, then a PRV is already built in.
If you do a larger batch in the future and you're concerned about headspace, just add a bit of fermcap.
Whisky River
Well-Known Member
Obviously plenty of people ferment in kegs without incident, usually removing the poppet and using a blow off tube of some significant diameter, and everyone is free to do whatever they want. But it is worth noting for posterity that the PRV on a corny keg was NOT designed to deal with the potential of being fouled by krausen. Fermenting in a keg is not a use case that the designers planned for, and the pressure built up in a keg could do some serious damage.
If you look at the PRV’s that are designed for use on high pressure capable fermenters you will see that they usually have about a 1.5 in bore with around 6 half inch vent holes. I think that gives a pretty good idea of what an engineer designing a PRV for a high pressure fermenter thinks is necessary.
Since we all love pictures, this is a brown ale I made a few years ago. I just made an identical batch this week in my SS fermenter (no pics) which completed active fermentation in 1 day. Note that the plastic fermenter has about 33% more surface area than a keg so the krausen would likely be even higher in a corny keg and could reach that height in a matter of hours.
If you look at the PRV’s that are designed for use on high pressure capable fermenters you will see that they usually have about a 1.5 in bore with around 6 half inch vent holes. I think that gives a pretty good idea of what an engineer designing a PRV for a high pressure fermenter thinks is necessary.
Since we all love pictures, this is a brown ale I made a few years ago. I just made an identical batch this week in my SS fermenter (no pics) which completed active fermentation in 1 day. Note that the plastic fermenter has about 33% more surface area than a keg so the krausen would likely be even higher in a corny keg and could reach that height in a matter of hours.
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Kegs are narrow, carboys medium-wide, bucket/conical fermented quite wide.
Assuming constant Krausen volume in the various vessels, you need more head space height in a keg to avoid a potential problem.
I often had blowoff from glass carboy fermenters (5 gal. in a 6.5 gal. carboy) . Never from my Flex+ stainless bucket, where I use 4mm EVAbarrier blowoff tubing with no problem.
Assuming constant Krausen volume in the various vessels, you need more head space height in a keg to avoid a potential problem.
I often had blowoff from glass carboy fermenters (5 gal. in a 6.5 gal. carboy) . Never from my Flex+ stainless bucket, where I use 4mm EVAbarrier blowoff tubing with no problem.
