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General Category => General Homebrew Discussion => Topic started by: frochild on June 24, 2011, 03:35:46 AM

Title: Moldy tasting beer
Post by: frochild on June 24, 2011, 03:35:46 AM
I just bottled a spruce honey pine ale.  When I was putting the beer in the bottling bucket it smelled like pine cleaner.  When I tasted it, it tasted like it had mold in it.  Yet I never once saw any evidence of mold.  I am wondering if this flavor has come from oxidization or going stale.   It fermented for a week, but I could not bottle it at that time.  Unfortunately, my other carboy was still in use and I could not rack the beer for another week.  To make things worse, it was another two weeks until I got to bottling it ... and  the temp of my house was 78 -80 degrees the whole time.

I also suspect there was a few hours with a small air leak- the airlock had been hit during some re-arranging and was found later tilted enough to think I may have lost the seal where the airlock goes into the carboy.   I have made about 10 beers, all outstanding.  I cannot be too disappointed here.  Besides my raspberry wheat just finished bottle conditioning and tastes it great.

Anyhow, if anyone has any insight to this I would greatly appreciate it.

Title: Re: Moldy tasting beer
Post by: thomasbarnes on June 24, 2011, 05:00:05 AM
Moldy notes are usually due to moldy soft plastic or rubber bits, like airlocks, hoses or fermentation buckets being left in contact with moldy surfaces, or being used for brewing after being put away wet so that mold grows on/in them. Mold aromas and flavors are very pungent and can easily penetrate plastic and rubber.

So, if your fermenter had mold in it (e.g., standing water) or if you were fermenting in a plastic bucket which was allowed to sit on a damp floor for a long period of time, your beer could have picked up a moldy smell even if there was no actual mold in your beer. Since mold is aerobic, actual mold in your fermenter would have formed fuzzy or slimy colonies on the surface of your beer after fermentation settled down. Given that your beer was only fermenting for 2 weeks, though, unless you're in a high mold environment (e.g., places where it's warm and wet) it seems a bit unlikely.

I wouldn't worry too much about the gap in the airlock, especially if it occurred early in fermentation when there was still a fair of CO2 being produced. The "overpressure" of the gas pushing out of  fermenter would have kept any bad bugs from getting into your beer.

My guess is that the mold notes came from the the spruce or the honey. Either the ingredients were actually moldy (unlikely) or you're just interpreting some aspect of the spruce/pine/honey aroma as being moldy.

It's also possible that you're interpreting some yeast-related compound (e.g., a phenol) as mold. Yeasts can sometimes produce smoky notes that can get interpreted as "peaty" or "earthy."

My advice is to not worry. Bottle the beer, let it condition for a couple of weeks and taste it again to determine if the moldy aroma is still there.

Title: Re: Moldy tasting beer
Post by: frochild on June 24, 2011, 07:14:57 AM
Thanks for the reply thomasbarnes, lots of great info I am sad to report that the little leak occurred after active fermentation ended.  That being said, I really am not too sure about it being an actual leak anyways.  Besides a bottling bucket, airlock/stopper, siphon hose, everything I used was glass. I do believe the pine contributed a majority of what constituted the off flavor, but it seems like something subverted the pine flavor.  I should note that two other people who tasted it with me, spit the beer out.   Either way, the beer has been bottled.  Here is to hoping it gets better.

Cheers
Title: Re: Moldy tasting beer
Post by: oscarvan on June 24, 2011, 11:47:17 AM
I agree with everything Thomas said. Let it sit in the bottle for a few weeks, and you may be pleasantly surprised.
Title: Re: Moldy tasting beer
Post by: frochild on June 24, 2011, 12:42:26 PM
I hope so!  Surprisingly, I am more interested in what happened than I am having a good tasting beer.  I remember when I started brewing, the thought of having a ruined beer, was almost overwhelming; all that work, time, and money ruined.  Now, its all about understanding and improving the process. If I can figure out what happened then I have made a major step in improving my brewing process.

Title: Re: Moldy tasting beer
Post by: bluesman on June 24, 2011, 12:55:17 PM
I would take into consideration how the green the beer is at this point. The flavor profile of the beer will significantly change at this stage of the game.

Could you post your recipe and process details?
Title: Re: Moldy tasting beer
Post by: jeffy on June 24, 2011, 12:56:59 PM
I hope so!  Surprisingly, I am more interested in what happened than I am having a good tasting beer.  I remember when I started brewing, the thought of having a ruined beer, was almost overwhelming; all that work, time, and money ruined.  Now, its all about understanding and improving the process. If I can figure out what happened then I have made a major step in improving my brewing process.

This is a great attitude.  It's so much more refreshing to hear this than, "should I throw out my beer?"
Title: Re: Moldy tasting beer
Post by: Mark G on June 24, 2011, 01:03:38 PM
I would take into consideration how the green the beer is at this point. The flavor profile of the beer will significantly change at this stage of the game.

Could you post your recipe and process details?
I'd be curious to see the recipe too. If you have a beer with spruce and honey, those flavors may take a while to meld together properly. Put the bottles aside and try one every couple weeks to see how the beer ages.
Title: Re: Moldy tasting beer
Post by: frochild on June 24, 2011, 10:39:31 PM
3.3 lbs john bull plain dark malt extract ( had to use the mutons equiv)
1 2/3 lbs plain dried amber malt extract
2.5 lbs honey
3/4 lbs crystal malt
1/3 lb black malt
1oz centennial hops
1oz Amarillo hops finishing
1 oz pruce essence
yweast 1056

pitched at 78 degrees

OG 1.036
FG 1.011
Title: Re: Moldy tasting beer
Post by: oscarvan on June 25, 2011, 12:26:25 PM
Is it me or is that a lot of honey in a 5g batch? And don't have time to do the math right now, but that OG seems low with all that sugar.....
Title: Re: Moldy tasting beer
Post by: Mark G on June 25, 2011, 01:22:45 PM
Yeah, assuming a 5 gal batch, the OG should be around 1.056. That's a really high piching temp for that yeast. I'll bet the yeast contributed some off-flavors. I've never used spruce essence before, but I'll bet it's not playing nice with the yeast-derived off-flavors. Try waiting to see if the flavors mellow over time. Next time, you want to find a way to get your pitching and fermenting temp down into the 60's for better results.
Title: Re: Moldy tasting beer
Post by: frochild on June 25, 2011, 02:54:33 PM
The OG astounded me, almost as much as the final alcohol content being around 3.5%.   THe recipe called for a lot of honey in order to provide a kick while keeping the beer light.  I ended up adding 1/2 pound more honey and 1/2 pound more amber malt to strengthen it.  Everything about this beer has surprised me.
Title: Re: Moldy tasting beer
Post by: tschmidlin on June 25, 2011, 08:13:08 PM
The OG was measured wrong - it's just not possible to be that low with that much sugar added.  One with with adding syrups like honey or LME is that you have to make sure they are well mixed in before you take your gravity reading.  With that little actual grains I wouldn't even bother measuring the gravity, the calculated gravity will be close enough.

It happens all of the time here, with people asking why their gravity is so low when they are doing extract batches.
Title: Re: Moldy tasting beer
Post by: frochild on June 26, 2011, 12:39:03 AM
I need a wort cooler, and I should probably be brewing in my basement ... but, I waited too long to turn on my dehumidifier and it has gotten moldy down there.  WHile I am working on it and have my dehumidifier on, it was a bit late for my last few beers. 

That being said, I am surprised that the higher temps would have created this particular funny flavor, I would have though more butterscotch.  However, I do think think the best explanation for all of this is that the high temps, the long sit in the yeast, combined with the pine created a horrid tasting beer ... for now at least.
Title: Re: Moldy tasting beer
Post by: morticaixavier on June 26, 2011, 04:21:39 AM
I need a wort cooler, and I should probably be brewing in my basement ... but, I waited too long to turn on my dehumidifier and it has gotten moldy down there.  WHile I am working on it and have my dehumidifier on, it was a bit late for my last few beers. 

That being said, I am surprised that the higher temps would have created this particular funny flavor, I would have though more butterscotch.  However, I do think think the best explanation for all of this is that the high temps, the long sit in the yeast, combined with the pine created a horrid tasting beer ... for now at least.

I wouldn't worry about the length of time spent on the yeast. looks like we are talking around 3 - 4 weeks total, that's not a lot of time. I often leave even modest beers like this for 3-4 weeks on yeast just so the yeast has time to clean up any messes it may have had. It doesn't always clean things up but it doesn't make anything worse either. I think temp was the real problem. Search this forum for cheap temp control and you will find a plethora of ways to build, some for less than 50$ some for much more, a temp control device.
Title: Re: Moldy tasting beer
Post by: thomasbarnes on June 27, 2011, 01:58:13 PM
I need a wort cooler, and I should probably be brewing in my basement ... but, I waited too long to turn on my dehumidifier and it has gotten moldy down there.  WHile I am working on it and have my dehumidifier on, it was a bit late for my last few beers. 

It's relatively easy to make an immersion wort chiller.

Once the dehumidifier gets the mold levels knocked down, if the basement is still musty, you might need to scrub the walls and floor with dilute bleach or fungicide. If it's only slightly musty, it's probably OK to brew there as long as the air is relatively still (i.e., not a whole lot of dust in the air or temperature swings) and you keep any plastic fermenters off the floor (a pallet is good).

That being said, I am surprised that the higher temps would have created this particular funny flavor, I would have though more butterscotch.

Butterscotch and green apple (diacetyl and acetaldehyde) might be products of high temperature fermentation, but they're more typically a sign of poor or stuck fermentation since the yeast scavenges those products up as fermentation winds down. The classic "fermented too hot" off-characteristics are solventy, harsh "higher" alcohols and various phenols - smoky, medicinal, plasticy and/or spicy notes. Your "moldy" character could very well be due to phenols, since some smoky notes can be interpreted as being "peaty" or "earthy."

However, I do think think the best explanation for all of this is that the high temps, the long sit in the yeast, combined with the pine created a horrid tasting beer ... for now at least.

Even with a relatively high temperature fermentation, I don't think that yeast had too much to do with the off-flavor. Autolyzed yeast doesn't taste moldy, so much as "brothy" or like a vitamin B pill. If you've ever tasted nutritional "brewers yeast" or Vegemite or Marmite, it's like that flavor. More to the point, autolyzed yeast character takes weeks or months to develop.

My guesses as to the off flavor are:

1) Spruce extract. IMO, this stuff is nasty. If you must use it, a little goes a very long way. If misused, it can give an overpowering, artificial "Pine-Sol" character to your beer.

2) Fermentation temperature. The pitching temperature was way too high, but if you were also fermenting at 70+ F, then your beer is going to be producing all sorts of ugly off flavors.

3) Honey. Some strongly-flavored honeys can impart really unusual aromas and flavors. Something like wildflower honey can sometimes give very musky notes. Again, combined with the spruce and the yeast-derived notes, the effect could be interpreted as "moldy" especially if it's a more "musty," "earthy" or "mushroom-like" moldy character rather than mildew-like.

The bad news is that the spruce and phenolic character is going to take a long time to settle down. Store the beer in a cool place (like that basement of yours) for a few months, then taste it again to see how it's developing. If it's any good, let it sit for another 3 months and taste again, and so on to see if there's improvement.

If the beer is basically good, but just overpowering, consider using it as a blending beer to mix with another batch.

If it sucks, it's sink feed. Suck it up and treat it as a learning experience.   
Title: Re: Moldy tasting beer
Post by: frochild on June 28, 2011, 12:50:37 AM
Thanks to all above, there is some great information here.  It will be quite the waiting game now.