An issue (lemon flavor)

Hello, all. First time poster, but I've got this community to thank for a whole lot of help. Been reading posts here for about six months, so I know that you guys can probably help me fix this little issue.

Recently popped open the first bottle my 6th batch (an all-munich lager), and it seems to have a problem that's been recurring in my beers so far: about half the bottles in the batch have a strong taste of lemon. I've gotten this in all but two of my batches so far (even though it might've been present in those as well, only hidden by heavy hopping). Anybody's got any idea of what it might be down to and how to fix it?

Some suspects:

- Clear bottles. I know that you're not supposed to use clear bottles, however when I went to buy mine, the wholesaler was all out of the tinted ones. I've taken extra care to keep them in the dark, though, and I haven't gotten any really funky ones so far.

- Infection. I Suppose it would have to be the bottles in this case, since, as I said, about half of the bottles are just fine. I desinfect them, after cleaning, by putting them in a steam bath for circa 15 minutes. Not good enough?

- Yeast. I tend to get a lot of yeast "deposit" in my bottles. Don't know how to reduce it. I always ferment by way of primary - secondary - bottle.

- Sub-optimal PH. I haven't been using a PH-stabilizer, so I might have a sub-optimal PH value. I guess this might have an effect in it's own right, could it perhaps be the cause of the forementioned yeast deposit?

I'd be happy for any help I can get.

Clear bottles- would contribute to a light struck or "skunky" flavor

Infection- possible, but I'm not too ready to think lemon flavor would come from an infection

Yeast- When bottle conditioning it's unavoidable, are you getting more that you see in a commerically bought bottle conditioned beer?

What are you useing to clean your bottles? I'm wondering if that could have an impact.....

PH- never really worried about it myself, and I'm not sure that make for a lemon flavor

Regarding PH stabalizer - it often has a lot of sodium in it and can affect beer taste in sufficient quantities. I'm not sure if thats the reason for lemon flavors (and I'd expect the whole batch would taste the same) but I thought I'd mention it in an effort to eliminate variables.

How much yeast deposit is "a lot"? With sufficient time in the primary (only primary) fermenter, I get only a small amount of deposit, perhaps 1/8 inch (3 to 3.5mm) at most.

I bottle some of nearly every batch in clear bottles but by keeping them in the dark the flavor is the same as in the dark bottles.

I've not heard of an infection that could cause a lemon flavor but as each of us have different sense of taste I suppose you could get that flavor. I really doubt that this is a factor though.

I can get a lemon flavor by choosing the correct hop and then adding lemon zest or lemon juice. Other than that I've never had it.

You could be tasting yeast, which can cause a sour flavor. How careful are you when you pour?

As an experiment, try taking a bottle and pouring half of it into a glass. You should not get any yeast, so there should not be any sour notes. If you do get them, then that pretty much rules out the yeast as the source.

Now take the other half of the bottle, which has had the yeast cake disturbed from the first pour, and pour it into a glass, yeast and all. Does the taste from this pour resemble the lemon taste you are getting?

@ Joshua
- Nope, definitely not skunky.
- It's a sour and sweet flavour. Very much like lemon. But infections would tend against sour I suppose?
- I'm not using anything that's supposed to smell like lemon, if that's your drift.

@ mjohnson
- The issue would rather be that I wasn't using a PH-stabilizer, I figured.

@ RM
- That's about what I get. 1-3 mm of yeast deposit in a 33 cl bottle.
- Well, again, it's sour and sweet. Sort of like if you were to squeeze a bit of lemon into your beer. That's what makes it so annoying - every beer tastes like a Corona.
- Done a lot of variants, from noble to alpha-heavy.

@ LL
- I'll try that! Even though the carbonation tends to mix it all up.

Also, I read somewhere that aeration during fermentation might result in a flavour described as similar to fresh apple. Could that be it?

Pics!

What is that in the neck of the bottle? Looks like a mini pellicle.

Stackolee said:

@ mjohnson
- The issue would rather be that I wasn't using a PH-stabilizer, I figured.

Click to expand...

Yeah, theres been a lot of experimentation done with ph stabilizer. Bottom line is its pretty much worthless for stabilizing your ph (with some very narrow exceptions) and adds lots of sodium that isn't needed/wanted. I didn't want to bring it up and derail your thread, though. It might be worth while to read about it, though.

Doesn't sound thats a likely culprit though. How are your pitching rates and fermentation temps? I've had some goofy flavors from under pitching and having wild swings in fermentation temperature.

Yeah. The gunk in the neck of the bottle certainly doesn't look normal.

It sounds like it could be acetaldehyde, which can give a green apple flavor, and/or acetic acid which would lend the beer a vinegar like flavor and aroma. The two often come hand in hand with beer. If that is the culprit, the sour flavor would probably be the result of bacterial infection and so sanitation is your issue. It might only be acetaldehyde though, which would probably mean you just need to lager the beer longer. Do you think green apples describes the taste?

I agree with the last post about infection, but I always laugh when people bad mouth 5.2. My water is an 8ish. I put 5.2 into the water I strike and sparge with, and it's perfect 5.2 every time.
Try using oxyclean to remove all biofilm that may resist starsan, that should help if there is an infection.

@ revolutioned
Starsan is what I use, you use that in combination with oxyclean? Or oxyclean solo? Thanks for the tip!

@ mjohnson
Fermentation temps obviously vary from style to style, but I check regularly to keep within the recommended temps.

@ Others
So you think it might be infection, perhaps in combination with acetylhyde? That makes sense. I didn't think that pellicle looked normal either, but since some that taste weird didn't have it, I though that couldn't be the issue, figuring it was a side-effect of late fermentation in the bottle or something such.

Do you think the bottles would be the issue in that case? I don't use any kind of desinfectant for them, just cleaning with regular detergent followed by a steambath.
Or could the bacteria be spread unevenly in the fermentation vat?

Thanks everybody for the help!

Resolved! Probably hadn't manage to keep the siphon clean enough.

Used a jug to bottle rather than a siphon, and no lemon flavour this time around.