Siphon Pump Foam

[Slim M]

Recently picked up a super sucker antigravity siphon pump, and it works pretty good with water, cleaner, and sanitizer but as soon as I started sucking beer with it to move it from the fermenter to the keg I get foam on the discharge. Prior I ran cleaner, water, & Starsan through without issue.

I went ahead with filling the kegs & let the keg foam over until full while occasionally hitting them with co2. What got me was after filling the kegs I took the same exact setup at the same elevations and sucked water then cleaner then starsan without foaming issues. What gives? Figured if anything was gonna foam would have been the Starsan. I’ve never experienced this before with gravity/auto siphon. With both end of the hose submerged and no air leaks presumably why the foaming ?

 

[mac_1103]

I don't know, but unlike water, cleaner and Starsan, your beer has CO2 in it and that CO2 is going to want to come out of solution especially if the beer is warm. How much foam are we talking about?

 

[day_trippr]

Not just warm: taking the pressure on the beer negative is undoubtably going to cause CO2 breakout...

Cheers!

 

[Slim M]

I don't know, but unlike water, cleaner and Starsan, your beer has CO2 in it and that CO2 is going to want to come out of solution especially if the beer is warm. How much foam are we talking about?

By the end of the keg fill I had a few inches of foam flow over the lid. The line looked foamy only on the discharge side nice full hose on suction side.

 

[Slim M]

Not just warm: taking the pressure on the beer negative is undoubtably going to cause CO2 breakout...

Cheers!

Yeah this beer was around 68f and the ambient in the shop was around 95f. I wonder if the temp differential played a part. Do you think this foam is something to worry about?

 

[Bobby_M]

Temp will play a small part but the suction from the pump is also a factor. The vibration from the diaphragm operation is just the final piece of the puzzle that is causing the CO2 to crack out. The only possible issue I can see is that there is a theory that a given beer only has so much foam stability proteins to work with so if you cause a beer to foam up a few times, that it could have head retention issues in its final served form.

You should be able to minimize the foaming by a spunding (adjustable pressure relief valve) on the gas port of the receiving keg. Just set it to vent at about 10psi. That pump can make about 75psi on the output so no problem there. If you don't want to buy another accessory, you can also just put a grey QD on the gas port and run a hose down to the bottom of a 5 gallon bucket and make sure it's filled up pretty high with water (that will hold about 1/2PSI of back pressure. Finally, one last idea is to just back out the lid's pull ring PRV a turn or so to have it vent easier, but not at zero psi.

 

[Slim M]

Bobby_M so you’re saying push it in through the outlet post correct? This was my first time not using a gravity transfer with a siphon. I just hooked a hose & cane to both sides of the pump with suction side in the fermenter and discharge in the keg. The fermenter cane had a tip on it.

 

[Broken Crow]

I went ahead with filling the kegs & let the keg foam over until full while occasionally hitting them with co2.

Yeah..what @Bobby_M just said.. I've been using a similarly spec'd pump lately for filling kegs with beer not much cooler than room temp. The output pressure of the pump is pretty high and I've seen for my self that the higher a pressure I have in the recieving keg, the less foam I get. There is always going to be an initial amount of foam which, if filling a 5-gallon keg, will inevitably exit the gas post. To minimize it, I've had to put as much as 25-28psi in the recieving keg... at that pressure I only end up with about a pint glass worth of foam before the scale under the keg tells me it's filled. The colder the better, but it does need that back-pressure. Trying to do at anything less than 20psi, and I'd get up to a quarter of the keg full of foam. It took some trial-and-error, but as I've described it's working well for me now.

 

[Bobby_M]

Bobby_M so you’re saying push it in through the outlet post correct? This was my first time not using a gravity transfer with a siphon. I just hooked a hose & cane to both sides of the pump with suction side in the fermenter and discharge in the keg. The fermenter cane had a tip on it.

Oh, I thought you were doing that already. Let's back up. You should be filling your keg to the tippy top with water, then add 1oz of starsan concentrate. Close it up, roll it around on the floor a bit to mix. Then use CO2 to push all that starsan out into a bucket. Hook your pump output hose up to a black liquid QD and fill the keg through the out port.

If you're concerned about spending up 5 gallons of starsan and the co2 to push it out, you can also route your fermentation blowoff (source of free CO2) into your keg's liquid out port and then run a gas hose into a bucket of starsan for a blowoff. The constant outflow of CO2 will purge the keg of all oxygen during the primary fermentation. Either way, the keg should never be opened again or it's all compromised from there.

 

[Slim M]

Oh, I thought you were doing that already. Let's back up. You should be filling your keg to the tippy top with water, then add 1oz of starsan concentrate. Close it up, roll it around on the floor a bit to mix. Then use CO2 to push all that starsan out into a bucket. Hook your pump output hose up to a black liquid QD and fill the keg through the out port.

If you're concerned about spending up 5 gallons of starsan and the co2 to push it out, you can also route your fermentation blowoff (source of free CO2) into your keg's liquid out port and then run a gas hose into a bucket of starsan for a blowoff. The constant outflow of CO2 will purge the keg of all oxygen during the primary fermentation. Either way, the keg should never be opened again or it's all compromised from there.

Thanks very clever! Man I first started brewing and transferring to kegs in the early 2000s and was just taught to gravity transfer with a siphon setup and push a little Co2 in before during and after as the keg liquid level comes up the purge it a few times through the prv. I think I learned that from Complete Joy of Homebrewing back in the day. Guess I got somethings to learn.

 

[Bobby_M]

Thanks very clever! Man I first started brewing and transferring to kegs in the early 2000s and was just taught to gravity transfer with a siphon setup and push a little Co2 in before during and after as the keg liquid level comes up the purge it a few times through the prv. I think I learned that from Complete Joy of Homebrewing back in the day. Guess I got somethings to learn.

I think hazy IPAs turned out to be the canary in the coal mine as far as oxygen damage is concerned. That's not to say it's the only beer style that is affected, just the one that is most obviously ruined. Many people implement improvements in their process to correct the problems with hazies and then realize all the other beers are notably better for it.

 

[Slim M]

Bobby_M I think you’re probably right about the hazy IPA style being the canary. I like an hazy IPA once in a while but don’t care to brew one.

Early on in my brewing adventures I remember when almost everyone was also secondary fermenting in glass carboys. That was one practice I’m happy I ditched when I came back to brewing after my hiatus.

I’ve never done a closed transfer or really went to extreme lengths to try to completely purge kegs & I don’t think my beers taste oxidized, but heck I might not have enough sense to know. Might have to give it a shot though and see what I think.

 

[Slim M]

Starting thinking about this again because I’ve got some beer to keg next weekend and although I plan to maybe try O2 transfer in the future I’m going with what I got / know for now. So now to the questions.

1. My initial concern with the foam was O2 but if the inlet hose is fully submerged and I have no leaks is the foam even O2 or is this CO2 suspended in the beer?

2. Besides doing a closed pressure transfer what would you recommend trying to minimize this issue.

3. Is this even a valid concern?

 

[day_trippr]

My guess is the foam is CO2-powered from the gas coming out of solution due to the vacuum-induced pressure drop and itself isn't that big a deal, but otoh as @Bobby_M discussed there is the notion of "foam once" proteins that you would be "using up" which in turn would attenuate head formation and retention...

Cheers!

 

[Bobby_M]

I agree that there's no oxygen concern because the foam is pure CO2. You could just evaluate how your head retention is in these beers later on and see if it was, or will continue to be a problem.

 

[Slim M]

Just wanted to follow up on this. I transferred 10 gallons basically under the same temp, setup, conditions, & etc with the only difference this time was I increased the elevation of the pump in relation to the intake side / fermenter and I had no foam issues.

 

[Mutt98]

Just wanted to follow up on this. I transferred 10 gallons basically under the same temp, setup, conditions, & etc with the only difference this time was I increased the elevation of the pump in relation to the intake side / fermenter and I had no foam issues.

Could you describe your setup a little more. We tried to pump a beer recently and almost convinced ourself the foaming was oxygen related. Luckily we didn’t dump the beer. Im getting ready to pump into closed keg soon. I bought a spunding valve, but I’m wanting to take every step to reducing foam. (Cold crashing, back pressure, etc.)

 

[Slim M]

Could you describe your setup a little more. We tried to pump a beer recently and almost convinced ourself the foaming was oxygen related. Luckily we didn’t dump the beer. Im getting ready to pump into closed keg soon. I bought a spunding valve, but I’m wanting to take every step to reducing foam. (Cold crashing, back pressure, etc.)

My first attempt when I ran into foam issues
I had about 3 feet of hose on the intake and discharge side with one cane in the fermenter, and the other in the purge keg. The fermenter was about 2 1/2 feet above the top of the keg. The pump elevation was about even the bottom of the fermenter. Ambient temp is about 80°F. Beer temp was about 66 to 70 and I got lots of foam with this, but the beer ended up tasting fine and had pretty decent head retention.

My second attempt I had no foaming. I placed the fermenter and the keg on the table at equal elevations with the pump on the table. At the start of the pump, I pinch the discharge hose, slightly to cause a slight restriction, and then released it.

 

[Mutt98]

My first attempt when I ran into foam issues
I had about 3 feet of hose on the intake and discharge side with one cane in the fermenter, and the other in the purge keg. The fermenter was about 2 1/2 feet above the top of the keg. The pump elevation was about even the bottom of the fermenter. Ambient temp is about 80°F. Beer temp was about 66 to 70 and I got lots of foam with this, but the beer ended up tasting fine and had pretty decent head retention.

My second attempt I had no foaming. I placed the fermenter and the keg on the table at equal elevations with the pump on the table. At the start of the pump, I pinch the discharge hose, slightly to cause a slight restriction, and then released it.

Gotcha. So, I’m guessing pumping up helps provide some back pressure. If I pump into a sealed, pressurized keg, that should take care of all the resistance I need. At least that’s how it works out in my pea brain.