Fusals?

[Sea]

Hey all,

Is there anything other than high ferm. temps that can produce wierd alcohol flavors?

I had a problem this summer with temp, and got a batch that tasted off, and assumed that it was the "hot" alcohol flavors I've read about in descriptions of Feusal alcohol taste.

However, I've since had 2! other brews that had a similar, though much more subtle aftertaste, and I know that neither of them got over 70 deg F at any time.

So, could there be another culprit?

Thanks.

 

[mr x]

What yeast were you using?

 

[jdoiv]

It could be fusel or one of the 'adelhyde type of flavors. Both are produced as by products of fermentation particularly when the yeast are stressed. Fusels are mostly detected when the temp gets too high for the yeast. Other causes can be poor yeast health, lack of O2, inadequate yeast amounts or oxygenation of alcohols.

How do you control the ferment temp? Do you filter your water? Do you use a starter or aeration system? I would focus on these areas as potential fixes.

 

[malkore]

fusals are a distinct 'hotness' kind of flavor...think about the first time you ever tasted cheap whiskey...that hotness (on a smaller scale) is how fusals taste.

would you call the flavor 'medicinal' at all? could be an infection, or un-rinsed bleach if you're using bleach as your sanitizer.

 

[Sea]

Damn, I spelt Feusals wrong in the topic title bar!

The yeast was S-05, so no starter. I've only done about 9 AG batches, and don't have an oxygenation aid yet, so have been transferring to my primary rather noisily, maybe that's part of the problem? The water is fine, as I have had numerous great batches with it. Stress may be a factor, as I only pitched one packet, and probably was too lazy to even re-hydrate.

 

[FlyGuy]

A few years ago, I had issues with fusel alcohols spoiling my brews. High temperatures are a key culprit in these circumstances, and things are exacerbated by stressed yeast, as jdoiv mentioned above. In my case, my temps weren't all that hot, but the combination of under-pitching and under-aerating caused all sorts of problems (namely hot, fusel'y alcohols and lots of ester/phenol production). Perhaps this is why these off flavours are more common in higher-gravity brews, given that it is harder to aerate and pitch adequate quantities of yeast for big brews. (This was certainly the case in my situation.) Anyways, as soon as I started oxygenating then fermenting in a cooler, temperature-stable room, all these problems went away.

Interestingly, over-pitching can also lead to the production of fusels or other off-flavours in beer. I suspect it would have to be a fair amount, but it might be something to consider before pitching a brew onto a yeast cake in the primary from a previous batch, like some advocate.

 

[bitteral]

In Palmer's book, he lists that <b>over-aeration</b> as a possible source of fusel alcohols, as well. That really surprised me, but I just found it in his book this past weekend.

In my case, I'm really thinking that might be the cause of the somewhat strong alcohol taste in a couple of my brews. In each case, I used a good started, and very rigorously shook my fermenter for several minutes to aerate it. Could I have over-done it? Only time will tell for me. In the next batches I do, I will more moderately aerate my wort. (And by the way, I did wait until the wort cooled entirely to 70F before putting it into the fermenter and aerating it.

 

[FlyGuy]

In Palmer's book, he lists that <b>over-aeration</b> as a possible source of fusel alcohols, as well. That really surprised me, but I just found it in his book this past weekend.

In my case, I'm really thinking that might be the cause of the somewhat strong alcohol taste in a couple of my brews. In each case, I used a good started, and very rigorously shook my fermenter for several minutes to aerate it. Could I have over-done it? Only time will tell for me. In the next batches I do, I will more moderately aerate my wort. (And by the way, I did wait until the wort cooled entirely to 70F before putting it into the fermenter and aerating it.

As far as I know, it is not possible to over-aerate if you shake your carboy. The max O2 you can get into solution with this method is 8 ppm.

 

[TexLaw]

Wild yeasts also can produce fusels. You could have gotten a contamination this summer that lingers in your equipment.


TL

 

[Sea]

Good Info here, I know where to start. Thanks boys.

 

[Poppy360]

As far as I know, it is not possible to over-aerate if you shake your carboy. The max O2 you can get into solution with this method is 8 ppm.

Yup, you're right.