Plastic Favors in Pumpkin Ale Two Years in a Row

[JonasWepel]

I've tried brewing pumpkin ales for the past two years. Last year, I brewed an extract based beer with pre-baked, canned pumpkin and spice added at the boil. I fermented in a plastic bucket with dry S-05 and the beer had a significant plastic/band-aid smell and flavor. It was undrinkable. I assumed I had an infection and dumped the batch.

This year, I brewed an all-grain pumpkin recipe from AHS. This time, I baked my canned pumpkin and added it to the mash. I added spice to the boil. I brewed in a glass carboy with windsor ale yeast. I just cracked open my first beer after 4 weeks in the bottle and it had an identical plastic/band-aid taste as the previous year. I typically brew 5-6 batches a year and these are the only two batches that had this problem. This leads me to believe its not an issue with highly chlorinated water causing these flavors. Also, I fermented both batches in a swamp cooler type setup, with water consistently held under 70°F (I believe temps were likely between 64-68 for most of fermentation).

The only similarities between these two batches are 1) adding canned pumpkin (canned pumpkin baked prior to use). 2) Adding spice to the boil. 3) Brewing occurred in late August/September. With that info, is there anything I haven't considered when brewing a pumpkin beer that would lead to these off flavors? It seems like a strange coincidence that of the last 12 or so beers I've brewed, only the pumpkin beers have this off-flavor.

 

[captainL]

My guess is the spices. I made a winter warmer last year with fresh ginger and cinnamon. Weird flavor. Still have a few and I can't believe I drank as much as I did. Ick. Plastic flavor.....maybe. What spices did you use?

 

[JonasWepel]

Both batches used a combination of cinnamon, nutmeg, and orange peel. I've considered the spice may be the source of the problem, but as prevalent as spice is in brewing, I can't think of any reason why it would contribute to these flavors. I'm curious if there is a water chemistry aspect that should be considered when using these spices... perhaps there is something in my water supply that doesn't combine well with spices in the brewing process. For what it's worth I do pre-boil all water in my mash and sparging processes to reduce the effects of chlorine, and then cool the water down to the desired temperature for these processes.

 

[skiingimpy]

Just as a heads up, if your water supply authority uses chloramine instead of chlorine, and many do, pre boiling the water is not going to eliminate the chlorine in the ions because they are not free chlorine, but are bound with ammonia ions, which makes them persistent in water. To avoid this you can use a campden tablet (potassium metabisulfite) which will react with the chloramine, breaking it down so the chlorine will vaporate almost immediately.

I have noticed a significant increase in the quality of my beer since I started using the campden tablets.

It sounds like chloramine might not be the cause of your issue since it doesn't come up in any of your other beers. But to my way of thinking, if your water supplier does use chloramine, campden tablets would be the only way to really rule out a chlorophenol problem.

 

[Mikespunchlist]

Yesterday I saw some hollow plastic pumpkins at Wal-Mart. Maybe that's where the got the pumpkins to fill the cans?

 

[JonasWepel]

I checked with my water supplier and they use chlorine. Your post did make me read more about de-chlorinating tablets, and I think I'll try them next batch. Pre-boiling on the stove top adds some serious time to my brew day.

Anyway, after doing a lot of reading I'm starting to assume this is a coincidence and both batches were infected. I suspect my bottling bucket spigot is the culprit as I didn't taste these off-flavors prior to bottling.

 

[mac21]

I had a similar issue with a dunkelweise that I made. I really think it might have been the iodine based sanitizer that I used. Maybe I had a bit left in the keg or didn't dilute it enough and it stuck to the sides.