Off Flavor Help

[Clay26]

I have been getting some off flavors in most of my brews recently. Mostly it has been a green apple flavor which is usually associated with stressed yeast. To try to alleviate this, I built a fermentation chamber. My latest brew was the Russian River Row 2 clone. I fermented at 64 degrees with US-05 and then after 1 week slowly ramped up to 68 degrees. Total time in the fermenter was 15 days. I kegged/dry hopped today and there is a slight apple aroma. Less apple than previously but now there is a metallic/penny flavor. Almost like your eating a mouthful of pennies. I'm hoping it gets better in the keg, otherwise its going down the drain.

These are all grain brews. My first all grain was the best beer I had made. After that the only thing that tastes good is a double ipa. Maybe the hops mask the off flavors? I am also using a RO/DI water filter and using Bru'n Water to adjust the water profile. I'm thinking of just going back to tap water to see if that is part of my problem.

The only other think I can think of to fix the apple flavor is to make a starter so the yeast isn't stressed. On the last batch I re-hydrated the yeast. Otherwise I just sprinkle on top. I am aerating using a paint mixer attached to a drill and mix the crap out of it.

Any help would be appreciated. I'm getting tired of making crap beer.

 

[sudsybrewer]

Are you pitching 1 pack into a 5 gallon batch? What's the OG on the batches? If it's a 5 gallon batch at low to moderate OG, then you probably don't need a starter (based on my experiences with beersmith software) You might want to calculate yeast pitching rates (mr. malty is free? Never used it though). I hear doing a starter with dry yeasts isn't a great idea.

Another factor that may stress yeast would be initial wort oxygenation.

How To Brew says the green apple flavor may mean the beer means more conditioning...
http://www.howtobrew.com/section4/chapter21-2.html

Cheers,

 

[wardens355]

Do you use a copper wort chiller? Do you tape the temperature probe to your carboy with some kind of insulation over it? I use a piece of cloth and styrofoam, but I imagine a cheap piece of pipe insulation would work. The wort can be significantly warmer than the ambient air. I don't think yeast contribute a copper flavor though... Some quick combing through threads, maybe old grain? Did you use the same base malt?

 

[Clay26]

sudsybrewer - These are 5 gallon batches. I am pitching 1 packet. I was thinking of trying liquid yeast and making a starter for that. OG has been ~1.050 - 1.065. Not huge by any means. For aeration I used to just stir it vigorously. For the last 2 batches I used the paint mixer on the drill to whip it up. This didn't seem to help any.

wardens355 - Yes, I do use a copper chiller. Always have. I am using a stainless thermowell for the fermentation chamber. Using an ale pail to ferment in. Could the plastic bucket be imparting flavors? The grain shouldn't be old but I have no idea. I got it from the LHBS the day before.

 

[biereblanche]

US-05 is cheap, pitching 2 packets is a super easy place to start. Remember sprinkling can decrease viability, so I'd suggest you've underpitched using one sachet. Also, could add another week before racking off.

Plastic isn't imparting a flavor unless you've scratched your bucket. Grains also shouldn't be giving a metallic or apple flavor.

 

[wardens355]

From Palmer:

"Metallic
Metallic flavors are usually caused by unprotected metals dissolving into the wort but can also be caused by the hydrolysis of lipids in poorly stored malts. Iron and aluminum can cause metallic flavors leaching into the wort during the boil. The small amount could be considered to be nutritional if it weren't for the bad taste. Nicks and cracks ceramic coated steel pots are a common cause as are high iron levels in well water. Stainless steel pots will not contribute any metallic flavors. Aluminum pots usually won't cause metallic flavors unless the brewing water is alkaline with a pH level greater than 9. Shiny new aluminum pots will sometimes turn black when boiling water due to chlorine and carbonates in the water.

The protective (grayish) oxides of aluminum can be enhanced by heating the clean pot in a dry oven at 250°F for about 6 hours."

If you're chiller was covered in green oxides, maybe that could be a contributor, but I assume you would clean any of that off.

 

[stankyhank]

I got metallic flavors once because I used a Brillo pad to clean my aluminum kettle. It gave it a nice shine but was way to abrasive. Switched to a gentle go-over with a sponge and haven't had a problem since. Appley flavors will go away after some condition time.


Sent from my iPhone using Home Brew

 

[Bigglesbrew]

I think others have spoken well to the metallic taste. It sounds quite likely to be something in your system adding the flavor.

The green apple flavor sounds like Acetaldehyde. This is usually temporary and a by product of the yeast metabolising sugar in the wort. I wouldn't worry about it at 15 days, it takes some time to be processed by the yeast, in my experience higher gravity = longer. Also, 15 days is a short time to rack straight to a keg. I don't think about kegging until 21-28 days, this gives the yeast time to work out any unwanted flavors.

+1 on a proper yeast starter