[amanosz]

I'm trying to troubleshoot a subtle sweet aftertaste in my beer. It's my first lager, a German pils so it's out of style.  Primary fermentation has just finished and about to be cooled for lagering. OG was 1.043 and SG/FG is 1.007.

I'm trying to troubleshoot whether it's something in my recipe (see below) or an off flavor in my process (maybe acetaldehyde or esters?).

Recipe is a German pils, 3 gallon batch
4.5lb pils
3oz carapils (could this contribute?)
Hallertauer mitt hops: 1 oz @60 min, 0.5oz@15 min, and 0.5oz@1min, for an estimated 34IBU.

Here's my process:

Mini BIAB all-grain, started mash at the recommended 149F but by the end (90 min), it had dropped to 139. Still hit 80% efficiency. Vigorous boil for 90 min with wyeast yeast nutrient at 5 min.

Pitched dry cellar science German yeast, 12g packet into cooled wort (54), and held at 52-55 with an inkbird and chest freezer using temperature probe on side of carboy.  On day 8, fermentation was slowing down, and SG was at 1.015 so I did a D-rest at 63 for 3 days. Ramped down 3F/day to 49 and about to lager and here I am, at a FG of 1.007 and this sweet aftertaste.

Any ideas what may have caused this?

The yeast is supposed to ferment dry but not many reviews are out there confirming this. Unfortunately it was the only dry. Lager yeast my LHBS had in stock and I wasn't up for a starter. I don't think I underpitched (which may cause esters). The yeast was specified for 54-62 and I kept it below 54/55 but maybe I should have gone even lower? Could the low mash temp cause this? I've read too high can create unfermentable sweetness but I think that would still contribute to SG which doesn't seem the case here.

I'd welcome any feedback.

[ynotbrusum]

Any idea on the water profile?  Perhaps some sodium in the water?

[BrewBama]

First off, I don’t think you underpitched. You were spot on IMO.

I am wondering about your measurements. Specifically, your hydrometer. Are you certain the 1.007 FG is accurate?  It should be a pretty dry beer at that FG. Dry beers don’t bring to mind sweet to me.

If that’s not the issue I question the hops. They may not have been the alpha acid% you calculated them to be. Your calculated IBU(s) should have given you a fairly bitter beer. If they were not to the strength you thought they were, you may have simply not added enough bitterness.

You might consider pouring two measurements of beer, dosing one with gypsum while leaving the other as a control in an attempt to get a dryer perception. If you like the results you could scale it up to dose the whole batch or simply dose each pint.

If you keg you could dry hop the beer to change the sweet perception.

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[majorvices]

Reading your post and your mention of "maybe acetaldehyde or esters" and "sweet" with an FG of 1.007 tells me you are picking up an off flavor that reminds you of "sweet" and that is going to be very subjective. Can you describe the off-flavor better? Apple? Butterscotch? Corn?

Maybe this will help

http://howtobrew.com/book/section-4/is-my-beer-ruined/common-off-flavors

[denny]

Low FG doesn't mean you won't  have a sweet beer.  That's up to the recipe . Sounds like maybe you underhopped.

[majorvices]

Low FG doesn't mean you won't  have a sweet beer.  That's up to the recipe . Sounds like maybe you underhopped.

At 34 IBUS? I don't think that's the problem

[denny]

Low FG doesn't mean you won't  have a sweet beer.  That's up to the recipe . Sounds like maybe you underhopped.

At 34 IBUS? I don't think that's the problem

34 calculated IBUs.  That may not be what it really is.  One test we did found that many beers varied from the calculated results by as much as 50%.  Your theory is good, too.

[BrewBama]

My concern is the HM hops. I’ve read they retain 52%-58% alpha acid after 6 months storage at 20ºC (68ºF). If they were stored longer or mishandled they may have been less (far less) bitter than advertised.


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[jeffy]

Since this sample was probably tasted with no carbonation, perhaps the CO2 will offset the sweetness.

[ynotbrusum]

Sweetness can be perceived in so many ways.  Is it simply the malty sweetness of the pils malt by chance?  Describe it in as much detail as possible.  It could be something as simple as oxidation, for example.

[majorvices]

Sweetness can be perceived in so many ways.  Is it simply the malty sweetness of the pils malt by chance?  Describe it in as much detail as possible.  It could be something as simple as oxidation, for example.

I pick up oxidation as a "sweetness" sometimes. Kind of like vanilla.

[Saccharomyces]

A F.G. of 1.007 should be a dry beer.  The beer could lack bitterness.  However, the flavor of pilsner malt definitely leaves a graham cracker sweetness on the tongue.

[tommymorris]

Maybe after carbonation and conditioning the beer will improve.

[amanosz]

First off, I don’t think you underpitched. You were spot on IMO.

Good to hear.

I am wondering about your measurements. Specifically, your hydrometer. Are you certain the 1.007 FG is accurate?  It should be a pretty dry beer at that FG. Dry beers don’t bring to mind sweet to me.
[/quote/
I think so.  It was measured with a hydrometer.  Agree that 1.007 should be dry, which is why I'm surprised, and am suspecting esters or acetaldehyde instead of residual sugar.

If that’s not the issue I question the hops. They may not have been the alpha acid% you calculated them to be. Your calculated IBU(s) should have given you a fairly bitter beer. If they were not to the strength you thought they were, you may have simply not added enough bitterness.

It was based on the AA content specified on the package, but I suppose if it was an old batch, it could have decreased, as someone else mentioned.

You might consider pouring two measurements of beer, dosing one with gypsum while leaving the other as a control in an attempt to get a dryer perception. If you like the results you could scale it up to dose the whole batch or simply dose each pint.

Curious what does the gypsum do?  Just change the water profile to emphasize the hops over malt/sweetness?  Here's the profile I was aiming for:

50ppm CA, 4ppm Mg, 16ppm Na, 55pm CL, 58ppm SO4

If you keg you could dry hop the beer to change the sweet perception.

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Unfortunately not, will be bottling.  I think i'll wait it out and see how the cold and carbonation affects things

[amanosz]

My concern is the HM hops. I’ve read they retain 52%-58% alpha acid after 6 months storage at 20ºC (68ºF). If they were stored longer or mishandled they may have been less (far less) bitter than advertised.


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There was definite hops bitterness there.  After a couple of successive tastes, the sweet aftertaste seemed to go away and the hops were definitely there.  But good to know about this issue for future batches!