Why do we use blow off buckets?

[scott isham]

Why do we use blow off buckets with unitanks? Let me explain. As I was cleaning kegs, I was staring at one of my blow off buckets and I remembered a time about 15 years ago when I visited another brewery and noticed the brewer there didn't have any blow off buckets on his fermenters. I asked why and he said he didn't need any. I said, "That's silly, of course you need them." He pointed at his 15 bbl. fermenter and said, "Do you really think that a bacteria, floating on a piece of dust is going to travel five feet up the CIP arm, make a 90 degree turn, travel another three feet, make another 90 and then drop through the spray ball where it will ultimately infect my beer?" I said, "I guess not." Then he said, "Remember, because of the aeration, you're going to have a positive pressure on the tank until fermentation starts, then it doesn't matter. After primary, when the gravity hits the right level, I just close up the valve and it's done. This is just a safer version of open fermenters. As long as there's a positive pressure in the tank, everything is fine." I couldn't find any problem with his theory. So, that's the question. Is he right? Is this one of those things we do just because everyone else does it or that's what we were taught? Honestly, regardless of the outcome of this discussion I will still use blow off buckets, but this is one of those things I think about to keep from going insane while cleaning kegs.

[FDBC_Eric]

I think the concept behind it is correct however there is still a chance. Even with positive pressure it is net positive pressure not even pressure across the board. So event at say a 0.001% chance it is still a chance none the less. Additionally you never know about the crawlers. So while the brewhouse may almost always be bug free, say a few insects came in on a palate. One of them is looking for a home and your blow-off arm looks cozy and away it goes. So my thought is basically better be safe than sorry.


On a side note: I completely agree about the odd thoughts during keg washing. It is how I normally battle all sorts of odd concepts while cleaning kegs.

[beerguy1]

Funny how the mind drifts as we wash kegs. I havent used a blow off bucket in 6 years for that exact reason and I have not had any issues with it. Its just more junk on the floor to trip over,clean and to get mold under plus the gnats love that stuff

[Thirsty_Monk]

Usually there is a CO2 coming out of blow off arm. Any crawlers will die as soon as they would try to enter.

[Junkyard]

If you knew for sure your fermentations weren't going to blow off into the bucket I suppose there would be no need but I also like being able to gauge my fermentation activity so I know when to increase the temperature to help things finish out.

[Bainbridge]

Yeah, to me it's more of the "blow off" issue than any contamination issue. What a mess. At least with a bucket you can contain it somewhat, or move it say closer to the trench. Depends on how full you fill your fermenters I guess.

There's also a safety element that makes me nervous. If you're venting off the CIP spray arm, there's always that chance that you could get braunhefe and krausen clogging up your spray ball and thus, your vent arm. So hopefully you've got a VPRV on there somewhere. And when it comes time to CIP the tank, if that ball is gunked really badly you get the joy of unclogging it before it sprays properly, if water pressure alone can't free it.

[barleyfreak]

but this is one of those things I think about to keep from going insane while cleaning kegs.

It may be too late in my case, but for others, I think a "top ten things I think about to keep from going insane while cleaning kegs" list is in order.

[TGTimm]

We started using blow-off buckets recently, after 18 years without, and I'm still pondering the utility or value of them. We use a spunding (PCV) valve (Handtmann) on the blow-off arm (not the CIP arm) of the ferm, set at a low value, which also functions as a very good check valve, so contamination should not be a problem under normal circumstances. If the PCV was to stick open, there is positive pressure on the line until we crash the tank, which we do under pressure with the PCV turned up, so, theoretically, nothing can get in the line.

So, the bucket is a belt-and-suspenders sort of thing--or is it? At high kreuzen, even a fifty-gallon bucket doesn't contain the mess from a 110 bbl ferm, so that argument is pretty much out. As a "lock" to prevent unwanted nasties from getting into the ferm, the Sanadyne we put in the bucket has been totally blown out by the second day (second hour, more like) of high kreuzen, and the bucket of foam and wort becomes a perfect medium for all those nasties to propagate in--and it's connected directly to the fermenter!

This isn't my call, but while you all are cogitating while washing kegs, I'm doing my thinking while running lines, soldering, welding, etc, and some of the same thoughts go through my non-brewing mind.

[soia1138]

At this point I feel like the blowoff bucket is nothing more than a comfort thing. It's nice to walk in the brewery and here a healthy fermentation ripping away. Other than that they probably do more harm than good. Its amazing how much back pressure there still is with the blowoff in place. We use a saison yeast blend which will give some sulfer unless its allowed to ferment open with no back pressure at all.

[kai]

Why do we use blow off buckets with unitanks? Let me explain. As I was cleaning kegs, I was staring at one of my blow off buckets and I remembered a time about 15 years ago when I visited another brewery and noticed the brewer there didn't have any blow off buckets on his fermenters. I asked why and he said he didn't need any. I said, "That's silly, of course you need them." He pointed at his 15 bbl. fermenter and said, "Do you really think that a bacteria, floating on a piece of dust is going to travel five feet up the CIP arm, make a 90 degree turn, travel another three feet, make another 90 and then drop through the spray ball where it will ultimately infect my beer?" I said, "I guess not." Then he said, "Remember, because of the aeration, you're going to have a positive pressure on the tank until fermentation starts, then it doesn't matter. After primary, when the gravity hits the right level, I just close up the valve and it's done. This is just a safer version of open fermenters. As long as there's a positive pressure in the tank, everything is fine." I couldn't find any problem with his theory. So, that's the question. Is he right? Is this one of those things we do just because everyone else does it or that's what we were taught? Honestly, regardless of the outcome of this discussion I will still use blow off buckets, but this is one of those things I think about to keep from going insane while cleaning kegs.

That sounds right but also wrong to me. Yes, so long as there is positive pressure in a tank there is no real need for a blowoff bucket. But, at the start of fermentation, if there is a lag time, the ferment may cool overnight which will create an underpressure and suck in atmosphere. And, when a fermentation finishes it may also cool and once again suck in atmosphere.

I consider a blowoff bucket to be insurance for the start of fermentation, and for when the exothermic phase of fermentation finishes and the tank may not be spunded, and/or there may be nobody in the brewery that day (or night) to ensure a tank remains under positive pressure.

[Benjybo]

Not too sure where I could put a blow off bucket....(!)


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[nmheppenstall]

I just like the sound of bubbles.

Nick
Odin Brewing

[briangaylor]

Not too sure where I could put a blow off bucket....(!)


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Looks like you have the largest and most integrated bucket of all

[kai]

Plenty of room for a Burton Union in the middle, maybe?

[liammckenna]

Blow off buckets allow you to kill yeast prior to release down drain.

Nothing is going to make it up that arm and into your fermentor during the course of fermentation and subsequent rest. Positive pressure or not. Negative pressure (ie when cooling the tank and the liquid and head space contracts) does present the possibility of pulling air (and its resident contaminants) into the tank.

Pasteur proved that with a swan neck flask.

Pax.

Liam