Fuesel alcohol off flavours

[ChrisMoss]

Hey guys,



I just brewed a batch that I'm pretty sure ended up with fuesel alcohol off flavours, but I have a question about whether that can include or increase bitterness.



I brewed a new recipe - NEIPA - turned out it was 10kg malt (5gal batch) instead of my usual 6kg, and I massively underpitched using only one vial of white labs Vermont ale yeast. I also didn't control fermentation temp and it probably sat at around 23-24c (75f). I also struggled to aerate it much pre pitching. So pretty much a lot of mistakes in one.



I spotted a hot flavour after it had fermented for about 10 days, and figured it's a drain pour. I just tried it one more before ditching and it left quite a long bitter taste - I used a small charge of bittering hops and everything else was hop burst after it had started to cool. Is this likely to just be a green beer flavour or could it be from the fuesel off flavours/stressed yeast?



Thanks!



Chris

 

[brandonnys]

You probably picked up the fusels because of the high ferm temp. At this point, age will mellow the fusels, but you're going to lose some of the hops from your NEIPA in the process. It's still beer, so a drain pour is not necessary. Wait and see is my advice.

 

[bradleypariah]

I know a lot of people think you can get a drinkable IPA in only a week or 10 days, and that can be the case sometimes, but some beers don't taste good for weeks, months, or even years. 75° is just barely high. Optimum temp for that yeast is up to 73°, so you're not dangerously high, but a little off flavor is to be expected since it's not perfect.

That said, you may just be tasting diacetyl, which is is perfectly natural, and will be easily absorbed by the remaining yeast if you just give it some time. How old is your beer now? It may be overly simplistic, but think of the 1-2-3 rule (one week primary, two weeks secondary, three weeks bottle or rest). That's six weeks before some people even consider drinking their beer. Worst case scenario, you throw it away, but don't get hasty. If your beer is still young, there's still hope. If you have an aging vessel, or something else to ferment another beer in (in hopes it'll be ready sooner) let this one sit for a really long time, checking it every week or so. If the off-flavors get absorbed better, dry-hop it and let it sit even longer, then drink it. If you don't have another vessel, cough up the five bucks for a paint bucket from a hardware store. I've got two buckets and three carboys; nothing helps your patience quite like having a pipeline. Make another easy beer right away (and do everything right this time!), and maybe it will be drinkable in 10 days. After you drink that new 5 gallon batch, perhaps the old beer will be ready. Good luck!

P.S. - If your off flavor was indeed due to under-pitching, I've heard your diacetyl rest will only be effective if you get your beer off the yeast cake. So transfer to a secondary. Dry hop it if you find it necessary. You only want the suspended yeast working on your beer to knock out that undesirable flavor. If those fattened, lazy yeast are laying on the bottom, they'll continue to bottom-feed and pump off flavors into your beer until you get them out of the equation. You may even want to pitch some fresh yeast again if your gravity hasn't hit target.

 

[65C]

I did a 6KG/23L with some new S-04 - room temp at 19-20C but the fermentation took off and blow off was varying levels of violent for 3+ days

first taste after 2 weeks was awful - alcohol/fruit/sweet - anyway I didn't bin it but I bottled half and put half in a polypin - a few weeks on I forced myself to drink the poly - it's wasn't great but it's nothing like as bad as it first tasted - I'll keep some bottles back to see if it gets better later

I regulate the first 5-7 days ferment temp now - to about 16-18C - I probably overpitch as I'm using yeast cakes but so far that doesn't seem to be an issue if it's not over temp - that temp in first few days really seems to matter for me anyway

 

[helibrewer]

Here's the run down from Gary Spedding:

The individual alcohols playing the most important role in beer flavor include propanols and butanols conveying alcoholic, wine-like, and ripe fruity notes; active amyl alcohol (a methyl butanol) presenting the characteristic “fusely” or boozy pungent note; phenyl ethanol, producing a pleasant rose or sweetish note; and tryptophol and tyrosol, exhibiting bitter, almond-like, or solvent-like taste characteristics. The yeast strain, fermentation conditions, and wort composition all have significant effects on the combination and levels of higher alcohols formed. Fusel alcohols will be present at higher concentrations in more robust and alcoholic beers such as barley wines and imperial stouts, partly because of stresses inflicted upon the yeast by high ethanol concentrations and more strenuous fermentations. Otherwise, in most beer styles they should not be perceptible or just barely so. As a group, fusel alcohols are a major part of the “alcoholic” perception of beer and overall core beer flavor.

 

[bigdongsr94]

The bitterness you taste is astringency due to high mash pH. I'm certain. The grain will lower the pH but IPAs have trouble doing so when the water has much of any residual alkalinity but if you added basically half, it didn't have a chance. Brew with RO water and add atleast 12 or so lbs per 5 gal. Even on that schedule I still add acid. Go 14-16 lbs or higher and it will lower pH. Get in line with how water works or only do the simple steps I said and you will have better luck.

 

[ChrisMoss]

Hey guys, thanks for all the replies. That batch was definitely a drain pour. Re: the water and mash ph, I'm in Manchester uk and have brewed other beers (including some pale ales and IPA) that have come out fine without that bitter taste - so I'm thinking it can't be that. I also use a teaspoon of 5ph to level the ph in the mash.

I've re-brewed using a different grain bill (much less fermentables) and have pitched at the right temp and held it at 16-18c for 7 days. I'm using white labs Vermont ale yeast - and I've noticed the airlock has completely stopped bubbling. Have I killed the fermentation with the low temps? It had got down to 16c at times I think. Started at 1.068 so going to test gravity today and see where it's at. Thanks again!

 

[65C]

the test should show

but my main brew temp is 16-18 now

sad you binned the other - I wager that was a drinker in a few weeks

I'm coming to conclusion high ferm temps is one of the biggest nos

great water in Manchester - if you're on the north side anyway