Last Two Batches Are Skunked

So, I've brewed three batches so far - all extract. The first was an IPA which sat in the primary for three weeks and has been bottled 2-3 weeks at this point. It tastes alright, but I'm figuring the flavor will develop as it spends more time in the bottles.

The second batch was a Scottish ale, which I was going to bottle on Christmas day. My FG turned out right were I was hoping, but when I tasted it, it was incredibly sour - beyond undrinkable. I fermented it in a 5 gallon glass carboy with a blowoff tube rigged to a growler with sanitizer in it. Hoses were all clamped down with tape to make sure that I didn't inadvertently expose it to the air. The fermentation was so vigorous that foam leaked out below the blowoff cap which left behind a nasty residue that prevented me from being able to look inside, so no pictures or anything of the top.

The third batch is an imperial stout. I used a liquid yeast starter for that one and, after finding out that the Scottish ale was nasty, I tasted it as well. It's only been in the fermenter a little over two weeks, but it has a similar sour taste to it as well. Not nearly as bad, but I'm wondering if it's headed in the same direction.

Now, I'm a really nervous to brew up another batch now. I made a yeast starter earlier this week for a tripel I was going to brew, but I'm afraid I'm doing something wrong and am just going to wind up dumping batch after batch.

I've tried to be really careful with sanitizing, but here are a couple of things that I'm wondering if it could be:

1. I didn't realize after the first batch that I could dismantle my auto-siphon, so I'm wondering if just soaking in PBW wasn't sufficient. I fixed this on the third batch and was able to soak both pieces in my sink.

2. I check the pH of my sanitizing solution prior to each use and make sure that it is sufficiently acidic.

3. My brew pot can only hold 3.5 gallons, so I boil 2.5 gallon batches and then add refrigerated bottled gallons from the grocery store.

4. I chill my wort in about 20 minutes down below 70 by adding the chilled water as well as placing the brew pot in a cold water bath. I don't cover the top of my brew pot because I don't have a lid.

5. I pretty much keep all my implements and hoses in Star-San until ready for use.

6. Spray bottle of Star-San anytime I open up the fermenter, which is rare - I've been more or less ignoring them for at least three weeks before cracking them open.

7. All of my carboys are glass and these were my first batches in them - so, never used before.

Some things that I'm going to start doing are sanitizing the outside of the gallon jugs before adding them to the wort and sanitizing my yeast vials before adding them to the starter flask.

Anyone have any advice / suggestions that might help improve my sanitizing process? I'm more than a little bit discouraged right now - blowing two batches in a row really sucks. I was just starting to get really excited to be brewing my own beer.

gmcastil said:

4. I chill my wort in about 20 minutes down below 70 by adding the chilled water as well as placing the brew pot in a cold water bath. I don't cover the top of my brew pot because I don't have a lid.

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In future I would work on covering the pot during chilling as exposing the cooling wort to airborne infections is an unnecessary risk.

What temperatures are you fermenting? And what yeast are you using?

If your beers are "skunked" as you said, then it has nothing to do with sanitization or anything like that.

Skunking in beer is the chemical interaction of sunlight and isomerized alpha acids from hops in fermented beer. Are you storing your carboys or bottles in direct sunlight? That's the only thing that would cause skunking in your beer.

Perhaps you're using the wrong word, but if your beer is skunked, then it's only from sunlight.

Relax dude. Your glass carboys will show you when you have an infection, meaning you will see it. Infection is your worry but not your problem, you seem to do a good job.

Look at the fermentation temp: a house a 72 means when fermenting an ale at room temp your beer is close to 80, near the top of the yeast threshold. I solved this problem with a rubbermaid tub filled to beer level and frozen coke bottles. Improved my beer 100%.

Bottle the stout as normal or with just a touch less than the normal amount of priming sugar. Let sit for 17 - 21 days, then enjoy. I like to do a 6 - 9 8 oz coke bottles to use as tasters. I put the first one in at 14 days, let sit for 2 day to let the co2 soak in.

Good luck and brew it up.

Sour beer is due to bacterial infections. Skunking, as Revvy says, is due to light exposure and really does smell like skunk.

Since you did say sour in other places, it comes down to sanitation. PBW is not a sanitizer, but it sounds like the infection is starting during the fermentation. You haven't said where you are brewing, but if it is in your basement, keeping everything clean and sanitized will be a problem.

Beg to differ on infections being visible. Lacto-bacteria do not form visible colonies.

Thanks for the correction guys, I thought "skunking" was slang for infection. Sunlight definitely isn't the problem - all my fermenters are outside of any type of direct exposure to sunlight and I use the cardboard boxes that my carboys came in slipped around them.

As to where I brew, that'd be the kitchen. I've only just started, so the propane setup in the garage isn't in my brewing budget yet.

On temperature, my apartment is usually around 68 degrees, although that does tend to swing a bit. The thermometer strip on the side of the carboy usually reads around there as well, perhaps a point above.

Yeast strains - the imperial stout was a White Labs WLP004 Irish yeast. I cold crashed the Erlenmeyer flask and poured off the wort above it and then swirled it around before pitching it to the wort.

Update: I tasted the liquid above the yeast starter I'd made the other day and it too had somewhat of a sour taste. Are infections really this easy to get? Is every thing that has a sour flavor infected? I'm really having a hard time being excited about brewing beer if all it takes is one bacterial cell to find its way into my wort and trashing five gallons of beer.

The liquid above a yeast starter is often sour.....that's because there's no hops in it to protect it. That's not a real infection and it won't ruin, or even be all that noticeable in your beer. Some folks boil a hop pellet or two with their starter wort to prevent it, but it really isn't a big deal.

It really is difficult to get an infection. In fact most of the time when a new brewer is positive he has an infection, it turnd out he just has noob nerves. Infections are really rare in homebrewing.

One thing to realize is that if your beer hasn't been fully carbed an conditioned, what you perceive as smelling or tasting sour is actually carbonic acid (co2) that hasn't fully gone into solution. A lot of folks panic if they've taken a taste or smell from a fermenter, and the beer hasn't even finished fermenting yet.

I did notice something, you said you only soaked your autosiphon in pbw. That's a cleanser and NOT a sanitizer. That won't really protect your beer.

What sanitizer are you using? Or is that it? If that is what you're using, then that's why your beers are getting infected, just that you aren't using a sanitizer at all.

Revvy said:

The liquid above a yeast starter is often sour.....that's because there's no hops in it to protect it. That's not a real infection and it won't ruin, or even be all that noticeable in your beer. Some folks boil a hop pellet or two with their starter wort to prevent it, but it really isn't a big deal.

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So, my yeast starter is probably ok? I was pretty sure I was going to have to dump it and start with a new one.

It really is difficult to get an infection. In fact most of the time when a new brewer is positive he has an infection, it turnd out he just has noob nerves. Infections are really rare in homebrewing.

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That's what I had been reading, which is why I really wasn't sure that I was getting infected batches.

One thing to realize is that if your beer hasn't been fully carbed an conditioned, what you perceive as smelling or tasting sour is actually carbonic acid (co2) that hasn't fully gone into solution. A lot of folks panic if they've taken a taste or smell from a fermenter, and the beer hasn't even finished fermenting yet.

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After three weeks in the fermenter, the Scottish ale was finished fermenting - gravity readings didn't change. The imperial stout has only been in the fermenter for about two weeks, and the OG on it was huge. I guess the reason that I'm freaking out is that my first batch didn't taste like this at all prior to bottling. It was an IPA though, with a lot more hops - would these have been masking the sour taste on that one? Everyone I've talked to seems to think that it should at least taste something like beer when you go to bottle it, not some ridiculously sour monstrosity that has to be spat out. Something just doesn't sound right about that.

I did notice something, you said you only soaked your autosiphon in pbw. That's a cleanser and NOT a sanitizer. That won't really protect your beer.

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Yeah, I guess I wasn't entirely clear on that - I was referring to soaking the auto-siphon in PBW being inadequate and that I needed to dismantle it in order to clean it properly. Everything gets put in Star-San prior to use - thought I'd mentioned that somewhere in my post. Also, it goes without saying, I don't rinse after sanitizing.

What sanitizer are you using? Or is that it? If that is what you're using, then that's why your beers are getting infected, just that you aren't using a sanitizer at all.

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I use a 5 gallon batch of Star-San that I store in a bucket with the lid on and each time I open it, I test the pH to make sure that it's still in the proper range.

Thanks for the reply Revvy - any other advice?

How are you making your starters? Where do you store them? What type of flask covering do you use.

can you pour one of your bottles, let it warm and degas and take a gravity reading?

like Revvy said, many times new brewers are anxious to try their beer, drink a bottle of green beer and get overly worried. most infections will cause your beer to continue to ferment down near 1.002 or lower. if the gravity is stable and on par with the gravity at bottling time, it's doubtfully infected. green beer can taste quite tart from the yeast still working on the priming sugar.

Looking back on previous posts.... I would say give things more time. Sounds like sour, green beer. You can hit your gravity in a short time ,but the yeast has to clean up to make decent brew.

Since you're just starting in brewing, knowing how to describe the flavors of your beer is really helpful to the more experienced brewers on this site. Here's the classic wheel of flavors:
BT - An Introduction to Sensory Analysis {flavorwheel]

And a page which attempts to explain how to use it:
BT - An Introduction to Sensory Analysis

I've had to do tastings of my questionable beers with this printed out in front of me, and it's really helped.

BOBrob said:

Looking back on previous posts.... I would say give things more time. Sounds like sour, green beer. You can hit your gravity in a short time ,but the yeast has to clean up to make decent brew.

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Thats a good point, Acetalaldeyde (Green apple/ jolly rancher flavor) can come a cross a sour note. I learned this in my BJCP prep class the other day that Bud light has a good amount of acetalaldehyde in it. A good test might be to get a bud light, and give it a good smell and taste. It comes on very strong the first taste. Think about green apples or green apple jolly ranchers, and it will be easy to pick up on.

If this is the sour flavor you are getting it is likely what Bob is talking about, beer that was racked off the yeast cake a little too early and is a little young.

One thing to taste for if you have an infected batch is Diacetyl, butter flavor or the feeling of a slick coating on your tongue. Souring bacterea like pediococcus or lactobacillus will produce a lot of diacetyl so if you have an infection with a souring bacteria you should detect diacetyl's presence in the beer.