[gimmeales]

In a matter of days my kegged Alt has turned to tasting like water with a bottle of ground aspirin mixed in.   It was alway dry and bitter (hopped above style guidelines with early and late Hallertau additions), but has since taken a definite turn from the floral, earthy hopiness that it was originally pimping.  I even had family who aren't beer drinkers asking for second or third samples at a party last weekend - now it's got a aspirin, or alka-selzter-like bite. 

With the time that's passed (kegged for ~5 wks), I'm guessing it's an infection of some sort, but have not yet found what causes a strong flavor of aspirin.

My serving lines could stand a cleaning - they are a little discolored from a Stout I brewed a year ago - would beerstone be causing this and if so, wouldn't that just affect the small amount of beer actually in the line?
Any suggestions are welcome!

[morticaixavier]

My first thought is acetic bacteria. Asprin breaks down into acetic acid when it starts to go stale. it is acetylsalicylic acid to start with and as it breaks down it ends up partially as acetic acid and other stuff.

actually my first though was over carbonation but you would have mentioned that.

[gimmeales]

Yeah, it's been carbed and pouring fine at ~8psi.  With the flavor coming on near the end of the keg, I wondered if the ratio of airspace to liquid somehow resulted in greater C02 saturation in the beer, but the C02 will only saturate to equilibrium of it's environment, right?

The only other time I've tasted something distinctly similar was with a Mild I brewed which I mashed way too low only, so after it was carbed, there was this thin, seltzer-water quality that was very noticeable.  Maybe that was acetic acid too?

[morticaixavier]

Yeah, it's been carbed and pouring fine at ~8psi.  With the flavor coming on near the end of the keg, I wondered if the ratio of airspace to liquid somehow resulted in greater C02 saturation in the beer, but the C02 will only saturate to equilibrium of it's environment, right?

The only other time I've tasted something distinctly similar was with a Mild I brewed which I mashed way too low only, so after it was carbed, there was this thin, seltzer-water quality that was very noticeable.  Maybe that was acetic acid too?

well seltzer sounds more like water chemistry issues but I don't know why that would show up after some time. I know what you mean though, I have made a few second runnings beers that turned out really thin and watery and therefore tasted of seltzer when carbed. could be a wild yeast thing, or some other organism that has continued to ferment residual sugars until the beer is too dry. I wonder, if you take a sample and de-gas it and measure the gravity perhaps you will see a drop from the original FG pre kegging. just a though.

[tomsawyer]

Aspirin is acetylsalicylic acid so a mild acetic acid could give you this flavor.  Dirty beer lines would be a candidate   Otherwise a high sulfate water can give its own bitter bite, but I don't think it would change with maturation.  I don't think its carbonic acid, head space doesn't really affect carbonation level from what I understand.

[majorvices]

Head space most definitely accelerates carbonation, which could increase as the keg was emptied. Probably not an issue at 8 psi though. Unless your regulator guarge is way off.

[bo]

Head space most definitely accelerates carbonation, which could increase as the keg was emptied. Probably not an issue at 8 psi though. Unless your regulator guarge is way off.

How does head space increase carbonation, once you get below the dome in the keg? It's the same surface area all the way down from that point.

[tschmidlin]

It depends on how you carbonate.  If the pressure is steady then it shouldn't speed carbonation, but if you turn your gas off (which a lot of people (including me) do because of leaks in their system) then more headspace will cause over carbonation faster if your beer/headspace are not in equilibrium.  If they are in equilibrium should have no effect, and if you keep the pressure on then I don't see how it would have an effect either.

[bo]

It depends on how you carbonate.  If the pressure is steady then it shouldn't speed carbonation, but if you turn your gas off (which a lot of people (including me) do because of leaks in their system) then more headspace will cause over carbonation faster if your beer/headspace are not in equilibrium.  If they are in equilibrium should have no effect, and if you keep the pressure on then I don't see how it would have an effect either.

More head space won't cause over carbonation any faster than with a constant pressure applied. In fact, the constant pressure will accelerate it, because by removing the CO2, the pressure will drop during serving and more CO2 will come out of solution.

One thing more head space will provide is a better buffer when the CO2 is removed, IE you can serve longer without the gas line hooked up.

[majorvices]

More head space definitely increases the speed of the carbonation of the beer, as long as it is under constant pressure. If you have a half filled bright tank and you hit it with 15 psi your beer will be carbonated in much less time than if you only have a half inch of head space. Try it sometime for yourself.

A quicker experiment you can try. Take full keg of flat beer with minimal head space and force carb by shaking at 30 psi. Not take a half full keg and try the same thing for the same amount of time. You will quickly see which one carbs up faster.

In the case of the OP, if his regulator is off (say it reads 8 but is actually closer to 18) then as the keg is being emptied he may notice that it gets more carbonated. Not saying this is the case, just a possibility.

[tomsawyer]

I just don't see carbonation causing a taste like aspirin.  I take enough aspirin to know what it tastes like.

[majorvices]

Harsh bitterness is what I think of from aspirin. I have definitely had unpleasant bitterness from both my alt and IPA when co2 levels got too high.

[bo]

More head space definitely increases the speed of the carbonation of the beer, as long as it is under constant pressure. If you have a half filled bright tank and you hit it with 15 psi your beer will be carbonated in much less time than if you only have a half inch of head space. Try it sometime for yourself.

A quicker experiment you can try. Take full keg of flat beer with minimal head space and force carb by shaking at 30 psi. Not take a half full keg and try the same thing for the same amount of time. You will quickly see which one carbs up faster.

In the case of the OP, if his regulator is off (say it reads 8 but is actually closer to 18) then as the keg is being emptied he may notice that it gets more carbonated. Not saying this is the case, just a possibility.

Absolutely, a half full bright tank will carbonate faster than a full one. The CO2 has to carbonate only half of the volume of beer. However, it will have nothing to do with over carbonation being any worse, unless you apply too much pressure in the first place. Then the half full keg will over carbonate faster.

If the OP allowed his beer to reach equilibrium when it was full, and it wasn't over carbonated then, when it dropped half way it wouldn't be ether, if the pressure remained the same. This is what Tom was saying.

[majorvices]

Yeah, but what I am saying is that perhaps he started out at 2 vol co2 but his regulator gauge is faulty and as the head space increases the co2 pick up increases as well and the flavor changes "over a matter of days". Just a guess.

[bo]

Yeah, but what I am saying is that perhaps he started out at 2 vol co2 but his regulator gauge is faulty and as the head space increases the co2 pick up increases as well and the flavor changes "over a matter of days". Just a guess.

If you're saying that a possible faulty regulator increases the pressure with increased head space.  I agree 100%. I'm only saying that it's not a function of head space, but rather surface area and that area doesn't increase as the volume drops in a cylinder.

That said, your half full bright tank will definitely carb faster than a full full one.  On a side not, your brights tanks are chilled to what temperature?

The one thing that I had never thought of, until kegging, is that shaking the beer with cause it to absorb CO2 faster. It seems odd, when you think about shaking a can of soda, which results in the opposite effect.