Another fusel alcohol question

[Eigenbrau]

Bear with me here as I may be answering my own question, but I could definitely use the advice of someone a lot more experienced than I am. This problem is killing me.

I switched to all-grain about 4 months ago and ever since I did, I've had some serious issues with strong (sometimes overbearing) alcohol flavors in my finished product. Fusel alcohols would normally be the initial suspect, but I've been using a temperature-controlled fermentation chamber and generally the temps sit around 62-68 degrees depending on the yeast. I have a strong suspicion that fusels are the culprit, but what I'd like to know is where the hell they're coming from.

My questions are: does mash pH have a strong affect on the final product, especially in regard to the fusels? My last mash pH done with an English Brown Ale was sitting around 5.8, which is slightly alkaline. I am sending my water off for analysis and will be using some compounds to bring this down once my results come in.

Secondly, and I know this is frowned upon by you guys (and by myself, trust me), is that I generally allow fermentation to conduct for 7-10 days, then transfer to a corny keg due to high demand on the final product. The keg is chilled and allowed to sit for 2 weeks on CO2. Some beers have had fusel issues to the point they're barely drinkable, some have been very mild, but still present. No one seems to mind it, but I know that these brews are not competition worthy at all.

The thing is, I know I'll be told to wait it out and let them condition longer (and I will, trust me), but why is the fusel-burn present straight out of the carboy? I didn't have this issue with extract and generally the "green" beer coming straight out of fermentation was perfect, minus a few extremely minor off-flavors. My all-grain brews are showing a strong fusel character right out of fermentation, and I'd just like to know if anyone has some ideas as to why. I'm running out of any clues.

Any help you guys could provide would be greatly appreciated.

 

[mrk305]

What kind of yeat are you using? Different yeasts are meant to ferment at different temperatures. Fusels are usually created by too high of a ferment temperature.

 

[mrk305]

Read #9 on this off flavor brew chart and tell us if that is what you are tasting..........

http://www.winning-homebrew.com/off-flavors.html

 

[Eigenbrau]

It is indeed the hot alcohol/solvent flavor. I've ruled out temperature as an issue since it's controlled and accurate to within +/- 1 degree. I've read that some ester compounds can cause the solvent flavor, but this is looking more like fusels. Several different strains of yeast are doing it.

 

[jkreuze]

How much yeast are you pitching relative to your quantity of wort, and what are you doing to aerate the wort?

 

[Eigenbrau]

How much yeast are you pitching relative to your quantity of wort, and what are you doing to aerate the wort?

For pitching on 1.050-1.060 wort, I make 500mL of 1.040 starter and let them sit on a plate for 24 hours. I've been doing that with no problems even since extract. Oxygen, on the other hand, could be an issue. I aerate using gravity to splash the wort into the carboy. Could lack of available O2 cause this? If so, it's just a matter of picking up a pump and stone later.

 

[Yooper]

It is indeed the hot alcohol/solvent flavor. I've ruled out temperature as an issue since it's controlled and accurate to within +/- 1 degree. I've read that some ester compounds can cause the solvent flavor, but this is looking more like fusels. Several different strains of yeast are doing it.

What about water chemistry? I wonder if you're getting chlorophenols and not fusels.

Does it taste like nail polish remover smells? Or like cloves? Or bandaids? Or is it just "hot"? Some high ABV beers will taste hot, of course, but not a 1.050 beer, normally!

 

[Eigenbrau]

No acetone and definitely no cloves. Doesn't taste phenolic. Just hot and alcoholic. My original idea pointed to aeration or water chem. I wish I were better with the chemistry and yeast metabolism.

 

[jkreuze]

I can't testify as to the accuracy of this, but it is from a Zymurgy article that's posted over at http://www.mrmalty.com/starter_faq.htm


"Q: I’ve heard that too small or too large a starter can be bad for the yeast. How is that possible?

Parker says putting a fresh vial of yeast into 500 ml of wort and letting such a small starter go to completion can actually leave the yeast less ready to ferment a batch of beer. The yeast do not rebuild their reserves and have very little increase in cell mass.

The minimum starter size for significant yeast growth from a vial or pack of yeast is 1 liter. One vial or pack into 1 liter results in approximately a 50% increase in cell mass.

Some brewers make a small starter volume (500 ml or less) with the sole intent of “waking” the yeast. When making small starters, it is best to pitch the entire volume at the height of activity."


But then again it sounds like you've been fine with your previous starters.

Your aeration sounds sufficient. You might try adding a pin-drop of olive oil, see if that changes anything. I have not tried this but some say it can substitute for aerating the wort (to some degree, anyway).

 

[sjbeerman]

What's your pitching temp? Also, what are your typical attenuations?

 

[Waunabeer]

Yes, what is your pitching temp? Fermentation temp is one thing, but if the yeast is pitched into wort that is too warm, fusel alcohol will be very noticeable. I've had this happen to at least two brews now. The good news is that the flavor of fusels has mellowed some over the past few months, but is still noticeable.

Also, aerate as much as possible to give those yeasties a healthy start.

 

[Eigenbrau]

Pitching temp is generally 75 degrees as it's about the lowest my plate chiller will get without running it for half an hour. I could try leaving it overnight. I like the Zymurgy article and will definitely try 1L starters in the future. For the time being, I'll pitch straight from the pack for lower gravity beers and see what happens.

 

[OldManHouston]

I'd suggest 1L starters and get that pitching temperature down closer to 70F at all costs! If you pitch at 75F and it takes 24 hours to get the wort down to 68F or so, then your yeast has had 24 hours to produce off-flavors related to temperature.

 

[Eigenbrau]

I'd suggest 1L starters and get that pitching temperature down closer to 70F at all costs! If you pitch at 75F and it takes 24 hours to get the wort down to 68F or so, then your yeast has had 24 hours to produce off-flavors related to temperature.

I'll try this recommendation in combination with some of these others. Thanks for your guys' help.

 

[shanman75]

Another thought.

Mash temp has a lot to do with the type of sugars converted. I've heard that mashing low can makes more simple sugars than mashing high. What temp do you target mashing at?

 

[Eigenbrau]

I mash in at anywhere fr 152-158. The initial dough-in has been cool the last few batches as I'm still figuring out the numbers on my equipment.

 

[albsbrew]

I have the same issue when I moved to AG. 6 batches down the drain and I haven't figured it out yet. Did you ever figure out the cause?

 

[SethMasterFlex]

As mentioned by a couple users 500mL starters will not grow new cells, it will just put our yeast in a ready state. You're still probably pitching a 1.060 beer by half the amount. Stressed yeasts can produce off flavors, excess esters, and fusels IIRC. I make 500-800mL starters for my Belgians because I'm looking for excess esters and fusels, but I use at least 1L for everything else. Use Jamil's pitching rate calculator and make bigger starters IMO.

 

[makomachine]

Sorry to revive an old thread but having a similar problem recently and not sure if the OP figured out what was going on or not. I'm getting a harsh bite to the sides of the tongue on my last three beers that I can't pin down. My last beer, a Citra Pale Ale was temperature controlled at 67F with a 2.5L stir plate starter with WLP001. Pure oxygen for 60 seconds and fermentation temperature monitored and controlled closely by thermowell. I've changed a few things in my process, so hard to nail down the cause.

Additinal data points:

I use bottled spring water from Walmart with no water additions.
I mashed at 153 with a protein rest at 131 for 15 min - mash out at 168
OG was 1061 and finished out at 1014
Pitched 8/13, kegged 8/23 - 12psi at 40F

This beer turned out a bit bigger than I intended due to higher efficiency on a new setup. That said, I don't believe it's just 'hot' as it is almost more of an astringency than fusel character. Obviously time will help but trying to perfect my process and feel there is something I could be doing to take my beers to the next level. Water chemistry is something I need to work on but not sure that's the problem here.