Green Apple Smell

I brewed a Black IPA awhile back with US-05 that had a strong green apple smell appear after kegging it. After some research I found that the beer was “green” and should have been allowed to sit in the fermentor for a few more weeks. I had never experienced this before and was surprised it was an issue since it was one of my first times to use a fermentation fridge and keep the beer fermenting in the low 60s. I recently brewed a pale ale with white labs 001 that had the same smell just not quite as strong. Luckily I caught this one during a gravity reading and an now waiting for the yeast to clean up the green apple smell.

The main reason I bought a fermentation fridge was to reduce fusel alcohol flavors that were sometimes present in the stronger ales I brewed. I had never noticed this green apple smell before though. My question is if anyone knows of a temperature range that won’t produce fusel alcohols or the green apple smell? Both problems seem to solve themselves with extra time in the fermentor, but if I can cut down the wait time of the ferment with temperature control that would be great.

Also I understand Wyeast 1056/ Whit labs 001/ and US-05 are all basically the same yeast but as anyone noticed more or less fusels or green apple smell with one brand over another?

Acetaldehyde = green apple. It is usually caused by stress on the yeast. Are you making a good sized yeast starter? Be sure to pitch plenty of yeast to keep the beasts happy. One other nice thing is that acetaldehyde supposedly boils at about 69 F. So you might want to warm up the beer for a week or so and see if it disappears with warm aging.

No I didn’t make a starter but I pitched two packs of US-05 in the black IPA with a gravity of about 1.070 if I remember right.

The recent pale ale I just pitched a vial of of white labs 001 (no starter). It had an OG of 1.065 which I know is a lot for not using a starter but my efficiency ended up being a lot better than what I thought it would be so I just pitched what I had.