1st time using blow-off tube: am I doing this right?

[GlowingApple]

I usually ferment in a plastic bucket, but wanted to try using my keg fridge as a temp-controlled fermentation chamber, and my bucket is too big. My 5-gallon BetterBottle fits beautifully, but I needed a blow-off tube (since I'm brewing a 5-gallon batch). I'm using FermCap (added during the boil), and after a day the kraussen isn't too bad.

I'm using the set up from Love2Brew, with 5/16" ID tubing through a stopper.

Is this tubing large enough? It doesn't seem any bigger than an airlock, but the usual route of 1" tubing directly in the carboy won't fit snugly into the opening of a BetterBottle.

Do I need to seal the other jug better? I know it can't be airtight, but I'm not sure why in the article they cut a hole in the milk jug rather than just leaving the cap off. I'm using a glass 1 gallon jug (see attached picture).

Also, what do you usually use in the other jug? I filled it with some StarSan solution, but it's starting to foam over.

 

[m00ps]

looks fine to me. I usually use 5/8" tubing with a 3-piece airlock without the 2 other pieces. Tubing fits snugly into the middle and ive never had issue with clogging

 

[kh54s10]

It is good, but I would pour out all but 3/4 inch of the sanitizer in case a reverse siphon is created. Then there is a lot less sanitizer sucked back into the fermenter. This might happen with temperature changes. Like if you turn off the cooling at the end of the fermentation.
I put a margarine cup in a large sauce pan (in case it overflows) with just enough sanitizer to keep the end of the tube submerged.
I use 7/16 ID tubing, no problems so far, larger is safer.
IMO a blow off is essential when using a Better Bottle. I start with one EVERY time.

Northern Brewer sells a setup for PET fermenters: http://www.northernbrewer.com/shop/better-bottle-blowoff-assembly

 

[kh54s10]

looks fine to me. I usually use 5/8" tubing with a 3-piece airlock without the 2 other pieces. Tubing fits snugly into the middle and ive never had issue with clogging

The 7/16" tubing that comes with the Northern Brewer assembly fits OVER the middle part of the 3 piece airlock.

Be sure to cut off the x portion at the tip of the airlock. That will clog easily.

Then again the bottom of the airlock is much smaller than 7/16" and probably smaller than 5/8" Maybe I will cut one much shorter than just above the x.

 

[hezagenius]

Looks good to me. If you are past high krausen, you could put an airlock back in. I usually only use a blowoff for 36-48 hours unless the krausen is still high.

FermcapS will control a lot of the krausen so you may not even need a blowoff.

 

[GlowingApple]

It is good, but I would pour out all but 3/4 inch of the sanitizer in case a reverse siphon is created.

Good call. I have much less liquid now. I also diluted the StarSan solution a bit (I think I made it too concentrated) and added a drop of FermCap. No more foam in that jug!

Northern Brewer sells a setup for PET fermenters: http://www.northernbrewer.com/shop/better-bottle-blowoff-assembly

Do you know what diameter tubing this is? It doesn't get great reviews, and I might be able to drill a rubber stopper on my own (we have a hand coring set at my work). The tubing I have now is small, so I think I would be more comfortable with something larger, like 7/16" (from my LHBS) or 1/2" (from Home Depot), if I can get a stopper that would fit it.

 

[kh54s10]

I believe the Northern Brewer PET blow off has 7/16" tubing. I think the low rating come from people having trouble with the stopper staying put when wet with Starsan. I must have great water because Starsan stays good for a long time, never gets cloudy, makes great beer with only filtering. And it doesn't seem so slippery as others complain about.

For tubing the bigger the better - less chance of clogging.

 

[RufusBrewer]

Thinking out loud.

If the santizer jar and the carboy on the same level, can you get a spihon going? I know if the sanitizer jar is higher than the carboy, the potential for a siphon is present.

Hard for me to imagine enough pressure differential being developed to "pump" the sanitizer into to the carboy, when they are on the same level and the end of the hose at the carboy is above the sanatizer jar.

 

[kh54s10]

Thinking out loud.

If the santizer jar and the carboy on the same level, can you get a spihon going? I know if the sanitizer jar is higher than the carboy, the potential for a siphon is present.

Hard for me to imagine enough pressure differential being developed to "pump" the sanitizer into to the carboy, when they are on the same level and the end of the hose at the carboy is above the sanatizer jar.

If you keep reading this site you will find that it happens. I am not sure how, usually when the temperature is lowered for a cold crash I guess. But, there are many threads like: "I had gallon of starsan sucked into my fermenter is my beer ruined?"

That is why I use a small cup in a larger catch pot with only enough starsan to keep the end of the tube submerged. If you have only a couple of tablespoons in an airlock, why would you need a gallon of it for a blowoff tube?

 

[GlowingApple]

Chilling the beer (normal temperature swings, or cold-crashing) causes the liquid, and the CO2 in the headspace, to decrease in volume (think of SG with temperature: density increases, SG goes up, as temperature goes down). Since the volume is decreasing it's pulling on the blow-off tube and sucking air back in. Since the purpose of the blow-off tube is to not allow air to suck back in, the liquid ends up being pulled up instead.

If you have a fairly long blow-off tube line and a small amount of liquid it'll fill the blow-off tube line and that's it. If it pulls in all of the liquid then some air can seep into the fermenter, but in my opinion a little air is still far better than sucking a bunch of liquid into the fermenter.

If you have the jug liquid level above the liquid level in the fermenter than once the tube is filled with liquid it'll act like a siphon and pull it all into the fermenter. If the liquid level in the jar is below the liquid level in the fermenter (even having the jar on the same level as the fermenter the liquid level in the jar will be far below the liquid level in the fermenter), and it won't act as a siphon, but could still suck some liquid back in if the line is too short or there's too much liquid (just like drinking through a straw).

Based on the replies here I modified my setup a bit. I got a #10 rubber stopper and used a 1/2" coring tool to cut a hole to just fit a 7/16" ID hose (9/16" OD). I added an intermediate trap (a glass jar with two holes cut in the cover and sealed with silicone RTV caulking). This jar should catch any of the blow-off (unless there's enough to fill the jar) and also any liquid pulled back will run into this jar instead of into the fermenter (unless so much liquid gets pulled in to fill this jar, which is why I still have as little as possible in the last jar on the left).

 

[kh54s10]

I have seen that system of a catch jar and a second vessel for the sanitizer. It has a name. I can't recall what it is right now though.

Sitting in a small cup of sanitizer; If there isn't enough sanitizer to fill the tubing all the way it would be sucked up a little way in the tubing until the end of the tubing goes dry then the sanitizer would run back out. The air passing through the sanitizer should be at least somewhat sanitized also.

 

[A4C]

I have seen that system of a catch jar and a second vessel for the sanitizer. It has a name. I can't recall what it is right now though.

Sitting in a small cup of sanitizer; If there isn't enough sanitizer to fill the tubing all the way it would be sucked up a little way in the tubing until the end of the tubing goes dry then the sanitizer would run back out. The air passing through the sanitizer should be at least somewhat sanitized also.

Burton Union

 

[kh54s10]

Burton Union

Yes! That's it!!!!