Another question about fusel alcohols

[JimG]

I am fairly new to brewing and have been suffering the temperature regulation issue this summer. I thought I had it solved when I recently brewed an Oatmeal Stout. My fermentation temperature ranged between 65-72 F. My brew has only been conditioning for a few weeks now. The beer appears to have a slight solvent-like aroma but it does not affect the taste as far as I can tell. This is still a young beer and I wondering whether I have a fusel problem or whether it is too young to judge. Any thoughts? Also, on a related note are certain malts or recipes more likely to produce fusel alcohols at detectable levels? Thanks! JimG.

I have two beers conditioning: the Oatmeal Stout and Jamil's Chocolate Hazelnut Porter. I am currently drinking Pliny the Elder and planning a new brew--probably a blonde ale

[beerking]

Fusels are due almost entirely to 2 things (independently):
1. Temperature during ferment. Generally, fusels are formed with a ferment over 75F, although the exact temp depends very much on the yeast.
2. Some wild yeasts produce fusels at any temp.

Your temps are not likely to have produced much in the way of fusels. Again, this depends on the yeast. A good kolsch yeast may well produce fusels at 65-72F.

In addition to what temp you ferment at, temperature stability is also important. If your temp fluctuates more than about 1 F every hour or two, or in a range beyond about +/- 5 F, you are likely to get all kinds of problems. Your 65-72 should have been fine in this regard.

[JimG]

Thanks for the help Beerking. I think I bumped into a troubling temperature. My measurements are made from the top of the fermenter, not inside. During the early, very active phase of fermentation, I am probably not getting an accurate temp measurement. Based on what you said I may have reached a problematic temp during part of the fermentation. The yeast I used was Irish Ale with a suggested fermentation high-side temp of 72F. The learning curve is fun but not without mistakes!

[beerking]

If you are measuring a temp of 72 on the top or the outside of the fermenter, your true wort temp is likely 77-80F (or even higher). That may well be the source of your fusels.
Try putting your fermenter in a bath of water with a t-shirt around it. Keep the t-shirt dipped into the water bath, and let the rest hang on the outside of the fermenter above the water. Have a fan blowing on the t-shirt, and you can lower the fermenter temp 10F below room temp.

[JimG]

Brewking,

Yes, thanks, that's a good idea. I will do it for the next run. I was still brewing in plastic (the gift that got me started) and the fermenter had a valve at the bottom so I could not immerse it in water. Instead I was setting frozen water bottles next to the bottom of the fermenter and enveloping both in a wet towel. I had a fan blowing on that. The thermometer sat underneath the wet towel on top of the fermenter. Even so, like you said, the inside temp was a good bit higher than I was thinking. I knew it would be but I did not understand the differential would be that great. Hence, my mistake.

Among other issues with my setup the low humidity here allows the towel to dry quickly and I wasn't keeping up very well. The "water bath" idea solves the problem. I now have a glass fermentation jug and I will do exactly as you say from here on out. Onward and upward I hope!

[leoglenwood]

If you are measuring a temp of 72 on the top or the outside of the fermenter, your true wort temp is likely 77-80F (or even higher). That may well be the source of your fusels.
Try putting your fermenter in a bath of water with a t-shirt around it. Keep the t-shirt dipped into the water bath, and let the rest hang on the outside of the fermenter above the water. Have a fan blowing on the t-shirt, and you can lower the fermenter temp 10F below room temp.


do you mean that the thermometer strip on the side of the glass fermenter is up to 8 degrees lower than the beer inside? wowza

[beerking]

do you mean that the thermometer strip on the side of the glass fermenter is up to 8 degrees lower than the beer inside? wowza

I doubt the strip attached to a glass fermenter (carboy) is off by that much. My GUESS would be a couple degrees at most. With a plastic fermenter, I would guess ~5F. I had the impression that JimG had a thermometer next to the fermenter, not attached to it.

JimG, the lower the humidity in your brewery, the more effective the t-shirt in a water bath will be. Just keep it wet.

[JimG]

Yes, it was a thermometer. Thanks again for the great feedback!

[leoglenwood]

degree ferment to do the Russian Imperial Stout in Jamil's extract book -
if I'm using White Labs 001 and I want to avoid fusels, I could do the T shirt idea sans a fan, and it might keep things down 6 degrees

or since it's a neutral yeast do I need to not worry too much?
(I've been brewing since Jan 08 and trying to brew my way through that extract 80 classic recipe book)

would BeerKing agree that if one's house is in the low 70s in the summer, that Belgian brewing and maybe leave the American ale yeasts alone until the fall - ?

and thanks for the knowledge!

[beerking]

degree ferment to do the Russian Imperial Stout in Jamil's extract book -
if I'm using White Labs 001 and I want to avoid fusels, I could do the T shirt idea sans a fan, and it might keep things down 6 degrees

or since it's a neutral yeast do I need to not worry too much?
(I've been brewing since Jan 08 and trying to brew my way through that extract 80 classic recipe book)

would BeerKing agree that if one's house is in the low 70s in the summer, that Belgian brewing and maybe leave the American ale yeasts alone until the fall - ?

and thanks for the knowledge!

WLP001 is a pretty clean yeast. Your temperatures will probably be OK (with the water bath), so long as you keep to lower gravity beers. I would thiink you could brew an APA, maybe even a moderate IPA (NOT an IIPA) and be fine. Your beer will probably be a little more estery than you prefer, but it would be OK (not a medal winner, but one all your beer buds will drink up before you can enter anyway). You may not even notice it yourself, depending on how good your palate is, and how closely you judge your own product.

One other thing that will help is if you have any floor that is tile directly on concrete, since that will also help cool things.

[leoglenwood]

thanks a lot for sharing your knowledge and expertise

final query, sort of a follow-up: should I, as the next few weeks promise
to keep my basement in the low 70s, just brew using Belgian yeasts, where temps around 73 produce good things in terms of esters and phenols

or will 73 with say WL 500 or WL 530 produce the fusel headache etc

I've been reading Brew like a Monk and it seems some folks brew Belgian beers in the 70s

is there a style other than Saison (which I just brewed my first of) that could ferment in temps under 75 comfortably, or am I off to Home Depot to create this awesome water bath and fan thing, which is brilliantly MacGyver

and do you have any book suggestions?

[markaberrant]

In my opinion, most Belgian yeasts should not be fermented in the 70s, at least not for the start and bulk of fermentation. Even Saison yeast should start off in the low to mid 60s.

WL500 should most definitely be fermented cool for best results.

And temperature is not all about fusels. It's about esters, phenolics, yeast health, attenuation and more.

[beerking]

I just brewed a Belgian Golden with WLP500. I followed the temp recommendations for Duvel in Brew Like a Monk, which started low but held in the mid-70s for the bulk of primary, then cold conditioned. It worked great. The beer is a lilttle sweeter in the finish than ideal, but just fine.

OBTW, look on page 232. I am the homebrewer and GABF judge mentioned there talking about Tripel vs BSG.

[markaberrant]

I've been told that WLP500 can get really fruity when fermented in the 70s. I've only used it once so far, on a small beer to build up the yeast, fermented it around 62-65F, and was happy with the results. I'll be making a Belgian Pale with it in September, and a Dark Strong in December.

[leoglenwood]

I just brewed a Belgian Golden with WLP500. I followed the temp recommendations for Duvel in Brew Like a Monk, which started low but held in the mid-70s for the bulk of primary, then cold conditioned. It worked great. The beer is a lilttle sweeter in the finish than ideal, but just fine.

OBTW, look on page 232. I am the homebrewer and GABF judge mentioned there talking about Tripel vs BSG.

"the yeasty spiciness"!

that's incredibly cool - but I will still call you Beerking, Mr.Brown.

[beerking]

"the yeasty spiciness"!

that's incredibly cool - but I will still call you Beerking, Mr.Brown.

I did think getting into Stan's book was pretty cool!