What are the disadvantages of using a blow off tube?

I have beening brewing for only a short time, I am on my fourth beer. I am currently brewing a west coast amber (more hops). The top blew off the primary on day 3. I cleaned and sanitized the top and airlock and put it back on. Then about 8 hours later the airlock was clogged again and I replaced it with a blow off tube. is there any disadvantage to a blow off tube vs. an airlock?

No, no disadvantage at all. It's just a little bigger.

Not a single disadvantage so far as I know. I don't even use an airlock at all on my conical - just a blow off tube from start to finish.

I don't think so. As long as you keep the other end submerged in water or preferrably sanitizer or vodka you should be fine.

As long as you're good about sanitation, there's isn't much of a drawback of using a blowoff tube. I use one probably 75% of the time.

Yooper Brewmistress said:

No, no disadvantage at all. It's just a little bigger.

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You'd like that, wouldn't you?

Yooper Brewmistress said:

No, no disadvantage at all. It's just a little bigger.

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Damn, so size does matter.

Can i use a blow off tube on all my brews??

Leedawggy78 said:

Can i use a blow off tube on all my brews??

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Sure! I do.

Leedawggy78 said:

Can i use a blow off tube on all my brews??

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Sure, it can't hurt.

Damn it, Yuri is right ahead of me every time!

Fast fingers.

The only disadvantage that I see with using a blow off tube is that they are pretty hard to clean. During the initial ferment, you might have such forceful activity that krausen blasts it's way through the hose. It eventually dries and cakes in there, and it's not fun trying to clean it out. I sometimes give up and end up replacing it.

I guess 2 possible solutions to that is get a long pipe cleaner snake, or maybe replace the blow off tube with an airlock after the main ferment is over.

Khirsah17 said:

The only disadvantage that I see with using a blow off tube is that they are pretty hard to clean. During the initial ferment, you might have such forceful activity that krausen blasts it's way through the hose. It eventually dries and cakes in there, and it's not fun trying to clean it out. I sometimes give up and end up replacing it. ....

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Spinkle some oxyclean in the tube, and soak in hot water in the sink-gets all the crusties out. They will stain over time, but I rinse with Starsan and don't worry about it.

At this point, I have officially joined the "anti-airlock" brigade...
I started using a blow-off tube, and have had nothing but good luck.

One thing I have noticed is that at high krausen, the foam is a nice thick rich dense mat, compared to my "airlock" days, when it would be lighter, airier bubbles that would fill the entire head space of a 6.5 gallon primary. I have looked at video after video on Youtube, and see the same thing over and over again. 6.5 gallon primaries with a blow off tube have a nice thick rich mat of yeast/foam, about 1-2 inches, those with airlocks are full to the top with loose airy foam.

One advantage to this is that it makes cleaning the carboy a whole lot easier. Another advantage is that you don't have to worry about cleaning the blow-off tube, if the foam never comes close to reaching it anyway. In looking at videos, there are tons where the airlock if full of foam, foam shooting out the top, etc. Then you are cleaning the airlock, the counter, the floor. You are pissed, your wife/girlfriend/roommate is pissed, the dog is pissed because he has this bitter sticky **** on his paws, and he does not want to lick it off... it just isn't a good thing. I have only seen one video of a nasty looking blow off tube, and the dude was fermenting in what looked to be a 5 gallon secondary. DUDE... if you are on here, what the hell were you thinking?!?!?!

Now, here is my theory on why this happens. When you use a blow-off tube, you are giving the co2 a way out of the fermenter that is as unrestricted as possible. I use 1" id tubing, about 6 feet of it, running into a bucket with 5 gallons of sanitizing solution that is left over from that days brew cleaning. With no major restrictions on the escaping gas, the pressure in the head space should be less than the pressure inside the bubbles, and the bubbles should break quickly and easily. When you use an airlock, you put some serious restrictions on how fast that gas can escape. This would result in at least some pressurization of the head space, and my thought is that this makes it easier for the bubbles to stay formed for a longer time, since the pressure inside the bubble is not any greater than the pressure outside the bubble.

Take this all with a grain of salt, as I am just a noob with only 7 batches under my belt, and only two of those were with the blow-off tube. There may be a ton of people out there who use 6.5 gallon primaries and large diameter blow-off tubes, and still have problems with too much foam, I am simply basing my comments on my own observations, and on what I have found while searching videos online.



[ame="http://www.youtube.com/watch?v=Fz-jkAGd3L0"]Thick rich dense foam[/ame]

I just use foam control and don't worry about blowoff.


TL

Yuri_Rage said:

Fast fingers.

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Bet Yooper likes those, too...

TexLaw said:

I just use foam control and don't worry about blowoff.

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Yep, I'm a recent convert to that method. I've currently got just over 5.5 gallons of 1.070 OG beer (Yooper's DFH60) fermenting in a 6-gallon better bottle using Fermcap-S from Northern Brewer. I started with a blowoff tube just in case, but it never quite made it up to the mouth of the carboy, and it's been on an airlock ever since.

Funkenjaeger said:

Yep, I'm a recent convert to that method. I've currently got just over 5.5 gallons of 1.070 OG beer (Yooper's DFH60) fermenting in a 6-gallon better bottle using Fermcap-S from Northern Brewer. I started with a blowoff tube just in case, but it never quite made it up to the mouth of the carboy, and it's been on an airlock ever since.

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Great... new products to try, that none of the LHBS's carry...

One disadvantage is you don't get that nice krausen residue on the ceiling.

As mentioned they can be harder to clean but if you are getting krausen in the airlock you are in real danger of blowing the top.

I usually replace the blowoff with an airlock after the first week so I can cleanup the extra bottle and give me more space in my cramped storage room.

Craig

I usually do primary in a 6.5 gallon bucket. Is there a chance of blowing the lid off one of these (with a 5 gallon batch and airlock?)

Is there any need to use a blow-off tube in secondary?

Blow-off tubes are problematic for me because I have pets who will knock over and/or drink from the receptacle and/or pull the tube out entirely. I don't have a temperature-appropriate enclosed place to ferment away from animal vandalism...

chris.

rabidgerbil said:

At this point, I have officially joined the "anti-airlock" brigade...
I started using a blow-off tube, and have had nothing but good luck.

One thing I have noticed is that at high krausen, the foam is a nice thick rich dense mat, compared to my "airlock" days, when it would be lighter, airier bubbles that would fill the entire head space of a 6.5 gallon primary. I have looked at video after video on Youtube, and see the same thing over and over again. 6.5 gallon primaries with a blow off tube have a nice thick rich mat of yeast/foam, about 1-2 inches, those with airlocks are full to the top with loose airy foam.

One advantage to this is that it makes cleaning the carboy a whole lot easier. Another advantage is that you don't have to worry about cleaning the blow-off tube, if the foam never comes close to reaching it anyway. In looking at videos, there are tons where the airlock if full of foam, foam shooting out the top, etc. Then you are cleaning the airlock, the counter, the floor. You are pissed, your wife/girlfriend/roommate is pissed, the dog is pissed because he has this bitter sticky **** on his paws, and he does not want to lick it off... it just isn't a good thing. I have only seen one video of a nasty looking blow off tube, and the dude was fermenting in what looked to be a 5 gallon secondary. DUDE... if you are on here, what the hell were you thinking?!?!?!

Now, here is my theory on why this happens. When you use a blow-off tube, you are giving the co2 a way out of the fermenter that is as unrestricted as possible. I use 1" id tubing, about 6 feet of it, running into a bucket with 5 gallons of sanitizing solution that is left over from that days brew cleaning. With no major restrictions on the escaping gas, the pressure in the head space should be less than the pressure inside the bubbles, and the bubbles should break quickly and easily. When you use an airlock, you put some serious restrictions on how fast that gas can escape. This would result in at least some pressurization of the head space, and my thought is that this makes it easier for the bubbles to stay formed for a longer time, since the pressure inside the bubble is not any greater than the pressure outside the bubble.

Take this all with a grain of salt, as I am just a noob with only 7 batches under my belt, and only two of those were with the blow-off tube. There may be a ton of people out there who use 6.5 gallon primaries and large diameter blow-off tubes, and still have problems with too much foam, I am simply basing my comments on my own observations, and on what I have found while searching videos online.

Tons of airy foam

Thick rich dense foam

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Hmmm, I think your reasoning is a tad off here. In a standard airlock, the air inside must only push maybe an inch or so of liquid out of the way. At 2.3 PSI/ft of water, that's a mere .19 PSI. Whereas the pressure in a blow off tube scenario is probably much higher. To find it, just measure the depth of the end of the tube (in ft) and then multiply by 2.3 to find the PSI. So if you tube is under 1 ft of water, that's 2.3 PSI, under 2 ft is 4.6 PSI, etc.

So even if your tube is only 6 inches deep, that's still 6x as much as in the standard airlock. If your 5 gallon bucket is 1.5 ft deep, that's 18x as much pressure as an airlock!

In a higher pressure environment, I would surmise that it is easier to pop bubbles, due to the greater stress inflicted on the surfaces. Thus in the lower pressure airlock situation, the larger bubbles with high surface area are able to stick around longer, resulting in your high krausen. With a higher pressure, larger bubbles with inherently more surface area are exposed to significantly more force, and so only the little bubbles can stick around.

Relative to pressure, any restriction in the tubing is very, very minor at these flowrates. It would only be significant at flowrates of much more than a L/min.

That's how it seems to me, at least.

@Zoot: Nah, no real reason to have a blow-off in secondary; an airlock will do the same job but in a smaller space, so it's probably the way to go for most people.

works for me...

The only disadvantage I have come across is that I use a thermowell in the beer to control my fermentation temps, and I have yet to figure out how to integrate it with a blow off tube. Currently, I use a stopper with 2 holes - 1 for the airlock and 1 for the thermowell. Love to hear ideas for a better way!

What's this foam method all about?

If you're talking about the foam control we mentioned, Google "fermcap S." It's a food grade surfactant (i.e., breaks up the surface tension) that will settle out so that you don't lose head retention. It also works great in your kettle to keep that foam under control.


TL

I am going to go against the grain here. Pun intended.

I have used blow-off hoses for about the past year. I use 6 gallon carboys for the primary. Most of my batches ended up puking into the hose which makes a mess to clean up if you want to be sanitary for the next brew. I also don't get a really airtight seal between the hose and the carboy mouth. When the bubbles stop through the hose, I can remove the hose, attach an airlock, and get 15 or 20 bubbles per second.

What I am doing now is fermenting at 62 to 63 degrees rather than 69 to 70 degrees. The fermentation takes a couple days longer, but the krausen never reaches the top of the carboy. I feel better about sanitizing an airlock than a blow-off tube, and I know that I am getting a good seal. After the main fermentation is done, I kick the temperature up to the high 60's to finish it off. I haven't noticed any negative taste effects.

As for the 5 gallon primary post, I did my first batch in a 5 gallon carboy filled about 3" from the neck using an airlock. I had done several batches of wine like this, and I didn't understand what all of the fuss was about. I brewed that batch on a week night. I went downstairs to check on the progress before work the next day, and boy did I have a mess on my hands. I was late for work.

Another disadvantage of just using a blow-off tube is that the air lock bubbles won't lull you to sleep at night

Willy Boner said:

Another disadvantage of just using a blow-off tube is that the air lock bubbles won't lull you to sleep at night

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The wife was just complaining tonight over dinner about the sound of the bubbles coming from the blow-off tube in the bucket of iodophore.

Willy Boner said:

Another disadvantage of just using a blow-off tube is that the air lock bubbles won't lull you to sleep at night

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Oh, man, that takes me back to my first batches. I forgot about how nice that is. There are some significant disadvantages to fermenting in a keezer.


TL

+1 on the Fermcap.

I've used it for two batches so far and am REALLY pleased! No blow off needed, only about 1" of krausen. Prior to this I was getting some pretty vigourous blow offs and losing a couple of pints of beer in the process. Now I can fill my carboys up pretty high and not lose any beer. I'm going to tap the first batch this weekend and I'm curious to see if there is any difference in the clarity.

Our local microbrewery uses it in the boil too. The brewer likes to push the limits of his boil kettle and he said that using the Fermcap has made a big difference although they still have to watch carefully for boilovers, expecially on the bigger beers (more initial protein)

What I'd like to know and haven't read anywhere is if you add it to the boil, do you need to add more when it goes into the fermenter? Does it get trapped in the trub in the boil kettle?

I love using it in the boil. Before I got my keggle set up, I was using a 30qt turkey fryer pot. One batch had maybe 2 inches of headspace, and I got it going without even a threat of boilover, without having to spray it or go crazy controlling the burner, etc.

It's also indispensible for boiling starter wort. Here's close to 900mL in a 1L flask:

It'll "bubble over" occasionally, if you're boiling it vigorously, meaning you'll get a small surge of those big bubbles like in the picture, but that's a VERY small amount of liquid and doesn't make a mess - no burning smell, and a quick wipe with a wet paper towel cleans it up after - there's really no threat of "foam over" like you'd get without foam control.

pjj2ba said:

What I'd like to know and haven't read anywhere is if you add it to the boil, do you need to add more when it goes into the fermenter? Does it get trapped in the trub in the boil kettle?

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When I have used it in the boil, I find I still need to add some in the fermenter. It almost seems like the additions to kettle and fermenter are separate - not sure if the stuff gets boiled off, or stuck in the cold break, or what. I don't really have much of a system, per se, I sort of add it as needed - I add maybe 5-10 drops to the kettle and then maybe 5-10 to the fermenter and then add a couple more drops if the krausen starts to climb too much.

I also find that I need to add Fermcap S to the fermenter, as well as the boil. I've only used it in the boil once, but I did look like a boilover was more possible toward the end of the boil. Since it's just a teaspoon for five gallons, I went ahead and tossed another teaspoon into the primary before adding the wort.


TL

According to John Palmer or Charlie Papazian, I forget which, having a blow off makes better beer.

Also if the bottle that your blow off tube goes into is sanitary and has sanitary water it's perfect for harvesting yeast.

abracadabra said:

According to John Palmer or Charlie Papazian, I forget which, having a blow off makes better beer.

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I remember Papazian said to blow off to get rid of some nasty oils??? or something like that. Looks nasty to boot. I blow off or use a larger fermentor.

abracadabra said:

Also if the bottle that your blow off tube goes into is sanitary and has sanitary water it's perfect for harvesting yeast.

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Sanitizer typically becomes ineffective when it gets dirty. After several days of krausen being blasted into a bottle of sanitizer, and the bottle itself being open to the air, I think it's quite safe to say that it's not going to be very sanitary any more - if it is, you probably also killed all the yeast that went into it. You could seal the blowoff bottle, use plain water instead of sanitizer (or nothing at all) and stick an airlock in it, in which case I think you're talking about a burton union...

But I do NOT think it is okay to go harvesting yeast from a bottle of sanitizer, yeast, and krausen that's been sitting open for several days.

One other very minor annoyance with blow-off tubes occurs if you use a shirt or box with a hole in the top to cover your carboy (say for cooling or to protect from light). It can be a pain to remove these covers because you need to feed the hose through the hole in the top. If you have tried this, you know what I mean.

I use rigid blow-off tubes made from PVC, which I like much better than plain hose, but they can be a PITA with a cover.

There are a few disadvantages to using a blow-off tube. It is used because you don't feel your head space is large enough to accommodate high krausen. The krausen is then piped off instead of just settling back down into the beer. Not only do you lose beer, but you lose a lot of the important proteins in the krausen that are head forming. I ferment 23 litre batches in 40 litre containers. I have healthy, vigorous ferments by hydrating dry yeast in water first before pitching (thus making my yeast much more viable than if I pitched straight into wort) and have never had to use a blow-off tube.

lol. The thread... its... ALIVE!!!

Homebrewtruth said:

There are a few disadvantages to using a blow-off tube. It is used because you don't feel your head space is large enough to accommodate high krausen. The krausen is then piped off instead of just settling back down into the beer. Not only do you loose beer, but you lose a lot of the important proteins in the krausen that are head forming. I ferment 23 litre batches in 40 litre containers. I have healthy, vigorous ferments by hydrating dry yeast in water first before pitching (thus making my yeast much more viable than if I pitched straight into wort) and have never had to use a blow-off tube.

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Well, you have a very unusual system having almost 50% headspace. Most home brewers are doing 5 gallon batches in one of 3 fermenters. A 6.5 gallon carboy, a 6 gallon Better Bottle or a bucket that is about 7 gallons.

Most blow offs are not so great that you will loose too much beer so the loss of beer or proteins is of no great concern.

For those using Fermcap-s, don't get too complacent. I have had 2 batches that had some blow off even with the Fermcap.

I have also heard warnings about sucking back a couple of gallons of liquid from the catch vessel. My question is why? You only need enough liquid to keep the hose end underwater. I use only about a cup of Starsan solution.