Is this bad? (picture included)

Whenever I drain the wort from my mash, I get air bubbles in the tube. Is this oxidizing my beer? Is this bad? If it is, how do I get rid of it? When I pinch the tube they go away for a minute but just come back when I let go. If I open the valve up full stream they go away, but then I am extracting the wort too fast, right?

Any suggestions would be appreciated.

if you are worried about it why not put a hose clamp on the barb
i dont think you need to worry that much about hot side aeration

People use a tube?

The bubbles are coming in from the hose around the barb, use a clamp. They go away when pinched because it is the flow that causes them and when full open they go away because the high volume hides them. I am not certain they are bad and I am not certain that the high flow is bad. Once the flow has started on my mash tun I open the valve all the way so I do not see a problem with starting it slowly then opening it up.

I'm not an expert but I don't think its an issue at all. Your not going to oxidize the wort in a negative way at this stage because splashing/air bubbles are beneficial prior to fermentation.

I recently read that to actually oxidize beer post fermentation and create off flavors etc. you would have to aggressively pump a lot of air into solution and/or splash etc. for an extended period of time. TIME is the actual factor (aging time) of the beer. You will probably drink it before the off flavors take over. All beer has some degree of oxidation. It would be a problem if it was a light style that was highly oxidized and stored in inadequate conditions for longer than usual. This probably wont happen. But in your case prior to pitching, its not a concern!

Relax. Don't worry. Have a homebrew!

Besides my previous advice to RDWHAHB, my opinion as a chemical engineer has a theory.

It kind of looks like your tube is kinked a bit right at the hose barb. This may be causing turbulent flow which is creating the air bubbles. The bubbles aren't going away because once the flow gets past the kink the velocity is too slow to overcome the bouyancy of the bubbles and push them out the tube.

Try replacing the tube or wrap the first few inches past the barb in duct tape or something to firm it up a bit and get the kink out. Maybe that will fix it.

Ok thanks, I'll try a hose clamp and see how that goes.

Phyrst said:

Besides my previous advice to RDWHAHB, my opinion as a chemical engineer has a theory.

It kind of looks like your tube is kinked a bit right at the hose barb. This may be causing turbulent flow which is creating the air bubbles. The bubbles aren't going away because once the flow gets past the kink the velocity is too slow to overcome the bouyancy of the bubbles and push them out the tube.

Try replacing the tube or wrap the first few inches past the barb in duct tape or something to firm it up a bit and get the kink out. Maybe that will fix it.

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Along these lines, get yourself some silicone instead of vinyl tubing and it wont kink. I used vinyl for my first few mashes and at those temps the tubing kinks very easily.

A number of solutions:

1) Don't worry about it. It's not going to oxidize your beer.
2) Ditch the vinyl and get some silicon hose.
3) Install a 45° or 90° elbow so the line won't kink.

paulster2626 said:

People use a tube?

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Yep! Two reasons- to alleviate any chance of HSA (even though it's not really an issue) and to use the tubing as a siphon to pull the wort out of the deadspace. I have a friend who doesn't use a tube at all, but his MLT is set up without much deadspace (manifold) and he just tips the MLT to drain it all. I have a false bottom over a bottom drain now, but when I had a cooler with a false bottom, I had to use a piece of tubing to siphon out my wort because otherwise I'd "lose" about 3 quarts of wort.

Oxygenation of wort doesn't cause off flavors. There's an entire step in the process dedicated to infusing as much O2 into the wort as possible. You only need to worry about oxygen once your wort has turned into beer.

Yooper said:

Yep! Two reasons- to alleviate any chance of HSA (even though it's not really an issue) and to use the tubing as a siphon to pull the wort out of the deadspace. I have a friend who doesn't use a tube at all, but his MLT is set up without much deadspace (manifold) and he just tips the MLT to drain it all. I have a false bottom over a bottom drain now, but when I had a cooler with a false bottom, I had to use a piece of tubing to siphon out my wort because otherwise I'd "lose" about 3 quarts of wort.

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Ahh, I am a tipping guy myself. Perhaps I'll try this mystical tubing method.

You can buy high temperature vinyl tubing at home depot (thicker wall than what you're using now, braided reinforcement) for pretty cheap. It won't collapse like your current tube. Also put something under your mash tun to tilt it (piece of 2x4) before you start running off to minimize the wort left behind. The softer angle will help with the tubing kinking.

Bubbles/liquid-air separation will always form at lower flows (during the beginning of the vorlauf), but go away when the valve is wider open.

Yooper said:

Yep! Two reasons- to alleviate any chance of HSA (even though it's not really an issue) and to use the tubing as a siphon to pull the wort out of the deadspace. I have a friend who doesn't use a tube at all, but his MLT is set up without much deadspace (manifold) and he just tips the MLT to drain it all. I have a false bottom over a bottom drain now, but when I had a cooler with a false bottom, I had to use a piece of tubing to siphon out my wort because otherwise I'd "lose" about 3 quarts of wort.

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Yooper, I'm unclear how you use the tube to "siphon"? I just give up on those 3 qts of wort usually, but I know there's some good fermentables in there.

jbaysurfer said:

Yooper, I'm unclear how you use the tube to "siphon"? I just give up on those 3 qts of wort usually, but I know there's some good fermentables in there.

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Well, you put the tube at the bottom of the vessel you're going to. Once you get below the level of the diptube in your MLT, if you have a tube going to the FB from the ball valve, and don't break siphon, you can "suck out" all of the wort under your false bottom by the siphon. Try it!

Yooper said:

Well, you put the tube at the bottom of the vessel you're going to. Once you get below the level of the diptube in your MLT, if you have a tube going to the FB from the ball valve, and don't break siphon, you can "suck out" all of the wort under your false bottom by the siphon. Try it!

Click to expand...

Edit: I reread. It IS a cool new brewing trick. Tks!

1. What kind of tubing is that?

and 2. You have nothing to worry about oxygen wise. No clamp needed, i promise.

This thread helped me prevent cavitation issues with my pump in my brew tonight. Probst!

Im not familiar to this thanks for the information.

ChillyCheese said:

Oxygenation of wort doesn't cause off flavors. There's an entire step in the process dedicated to infusing as much O2 into the wort as possible. You only need to worry about oxygen once your wort has turned into beer.

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The wort oxygenation step is carried out when wort has been cooled to yeast pitching temperatures whereas the concern with HSA is that when oxygen is added to the wort at the higher temperatures, the O2 bind to molecules of some compounds in the wort and this oxygen doesn't get removed by yeast but when the resultant beer is aged, the oxygen can be released to cause oxidation effects.

Phyrst said:

...This may be causing turbulent flow which is creating the air bubbles...

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If what you are saying is correct then the bubles shouldn't be air but wort vapour (as in steam is water vapour)? I agree with you fully in your explaination as the only other way to get bubbles in the tube would be a leak past the barb, if the OP pinched the tube as he said and it was an air leak there this should cause wort to leak out where the air was leaking in.

mattd2 said:

If what you are saying is correct then the bubles shouldn't beer air but wort vapour (as in steam is water vapour)? I agree with you fully in your explaination as the only other way to get bubbles in the tube would be a leak past the barb, ...

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I was thinking exactly this same thing but I guess it depends on what is happening at the out end of the hose - if it's above wort level, then if the flow isn't high enough air could get in and float up to where the bubbles are.

moleary said:

Whenever I drain the wort from my mash, I get air bubbles in the tube. Is this oxidizing my beer? Is this bad? If it is, how do I get rid of it? When I pinch the tube they go away for a minute but just come back when I let go. If I open the valve up full stream they go away, but then I am extracting the wort too fast, right?

Any suggestions would be appreciated.

Click to expand...

HSA is only a minor concern post boil, any oxygen getting into the beer between the mash and boil kettle will be driven off during the boil. If your concerned listen to the podcast link below from Charles Bamforth on the BN.

http://thebrewingnetwork.com/shows/475

HSA is only a minor post-boil concern, don't worry about it pre-boil, the oxygen will be released during the boil.