Bubbles in Siphon

I like to dry hop in my primary fermentor. Trying not to get a lot of hops and other stuff into my bottling bucket, I put a couple of pieces of cheese cloth at the base of the siphon as a filter. For some reason, even though the bottom of the siphon and filter is completely submerged, LOTS of air bubbles come thru the tube. Take off the filter and no bubbles at all. WTF! is it co2? why are these bubbles geting in and is oxidizing my beer?

 

Its just the gas coming out of suspension in the beer.

 

is it hurting anything? should I put a filter at the out flow end of the siphon tube instead?

 

if it is just CO2 it won't hurt it.. If it is O2 then bad. as long as there are no air pockets I don't see how it could be anything other than CO2. Should be fine.

 

A couple of possibilities.

It could be CO2 coming out of solution. The cloth may just provide the surface to get the CO2 to come out of solution. This WILL NOT harm your beer.

If you are using an autosiphon, it could be air leaking in from around the base of the piston seal. This would be AIR and IS NOT good. I may lead to early staling of the beer (if it lasts that long) The filter is slowing the flow and creating extra pressure drop which allows some air to sneak past the seal.

One solution to this is to put the autosiphon in the beer and let it set for a minute, and some beer will flow past the seal and be on "top" of the piston and help prevent air getting in (you suck up that "leaked " beer instead).

The next solution, which works for any siphon and bubbling issues. DON'T SIPHON SO FAST (smaller height difference). The slower you siphon, the smaller the pressure drop and the less likely you are to get air sucked in or CO2 to come out of solution.

 

Even though it's not under pressure there's still some CO2 dissolved in the beer, and it'll turn into a bubble given some kind of nucleation point (bumps on a rough surface, pieces of hops, etc). I think what's happening is that as it passes through that mesh any dissolved CO2 is nucleating into bubbles on the rough surface of the filter and getting sucked up the siphon.

HOWEVER: are the bubbles coming all the way up the siphon tube, or do they appear to starting somewhere else such as where the tubing connects to the racking cane? If it seems to be coming from some joint like this, then you probably are sucking in outside air and the filter might be affecting the siphon pressure or some such so that without it there's a lower pressure gradient or something. (that's just a wild somewhat uneducated guess, there).

If you can see the bubbles coming all the way up the siphon tube, I'm absolutely with 'theonetrueruss' in that I can't imagine how it could be anything other than CO2, and no it won't hurt anything.

 

Ah, yeah, I didn't think about the piston seal here. That's a really good point. I ran across some advice somewhere that I'll pass on here, too -- if you have an autosiphon, don't store it "put together." Remove the racking cane/piston from the siphon tube when you store it. In the disassembled position the rubber seal will be allowed to relax a bit, making a tighter seal when you put it back in the tube to siphon.

 

Ahha, the piston seal, i bet money that is the problem! Puting a filter on it would increase resistance and the sucktions is looking for the path of least resistance. I will try filling it with beer and see how it works, thanks!

 

I gave up on putting the bag on the end of the autosiphon. Now I put a jumbo size grain bag (sold by AHS) as a liner inside my bottling bucket, drape the excess over the top of the bucket and secure it with a bungee cord around the outside of the bucket. I siphon into the bottling bucket, then just lift out the grain bag along with any hop residue that came through the siphon (have an empty bucket sitting next to your bottling bucket so you'll have someplace to put the wet grain bag). I boil the bag before using it to sanitize it. Here's the bag I use:

http://www.austinhomebrew.com/product_info.php?cPath=178_33_403&products_id=1058