Liquid yeast question

[Nelrock]

After using dry yeast in my first 5 or 6 batches...I started using liquid Wyeast on the last few.
After the same 3 weeks or so bottle conditioning, I threw a few in the fridge, and when I cracked one...it was very green. 6 weeks and still...noticeably green. Even a bit of an alcohol odor to them.
My dry yeast batches were always pretty decent at the 3 week bottle point...I'm curious if its normal for liquid yeast to take so long?

I've got 4 batches in bottles. All brewed within a few days of each other. 2 caribou slobbers...2 hefeweizens.
Yeast pitched sub 70F. Kept fermenters in a water bath with the tub water maintained right in in 65F range.
All of them were 3-4 weeks in and bottled after taking a couple hydrometer readings.
I stay on top of sanitizing...plus all 4 have similar taste and smell.

Today...when I was bottling a hefeweizen...I noticed as I neared the trub, a strong odor of alcohol rose, the emptier it got. Very similar to the odor I smelled from the previous batches bottles, after opening one.

Never had this issue when I used dry yeast, which had me suspecting the liquid. Searched around but haven't found anything that jumped out as matching my situation.
Any information would be appreciated.

 

[dlaramie08]

Did you make a starter with your liquid yeast? There is not enough yeast in those smack packs to efficiently ferment a semi high gravity beer. This is evidenced by the off flavors associated with a stressed fermentation in your beers. Dry yeast has enough in one pack to provide a fine fermentation. Liquid yeast is great if you make enough of it.

 

[BlackGoat]

you need to make a starter with liquid yeast. Otherwise, once either dry yeast or liquid yeast get going they should function essentially the same. If you underpitch (i.e. not using a starter and only using a smack pack for a 5 gallon batch) you could stress the yeast out leading to off flavors. I'm wondering if its something specific with the yeast strain, perhaps you're fermenting a bit too warm. What strain were you using?

 

[Nelrock]

Wyeast 1332 Northwest Ale in the caribous. Wyeast 3068 Weihenstephan Wheat in the hefeweizens.
The first 2 I didn't make a starter, but did the 2nd 2 after I'd read it most recommending to.

 

[jro238]

Good advice about starters, but with hefes (I also use 3068 and love it) it isn't really a bad thing to underpitch a little bit. Brings the esters out a bit more due to the stress.

 

[BlackGoat]

Is it a rubbing alcohol smell? Since you got it with and without starters, the next thing I'd look at is your pitching and fermentation temps. You said you pitch below 70 and keep your water bath at about 65. Those both sound like good practice but for your next batch you might want to try lowering both your pitching temp and your fermentation temp. During peak fermentation, when temperature is most critical, the activity can generate quite a bit of heat in the fermenter raising the beer's temp quite a bit above the ambient temps outside. A warm fermentation can produce "hot" alcohol smells/flavors so you can get the nail polish remover/rubbing alcohol kind of thing going on from that. Take the time to get your wort down to about 60 before pitching next time, then rotate in some frozen water bottles during the first few days of the fermentation to keep the water in the tub at about 61-ish. That said, most people like to ferment there heffes a bit on the warmer side to get the banana/clove esters, so this advice might apply more toward the brown ales you've been brewing and any other style where you don't want a strong ester contribution from the yeast.

 

[flars]

How much of the fermentor was covered by water in the tub? If the water was 12 inches deep the wort temperature could have risen up to 10°, especially with WY3068. Fusel alcohols will be produced at ferment temperatures that were to high. The taste of fusel alcohols is very harsh and sharp though. Not quite what you described.

What was your bottle conditioning temperature? Did the bottle you opened form a nice lasting head with lacing on the glass as you drank? Too low of conditioning temperature will lenghten the conditioning time. The beer could still be green.

I have experienced this same type of aroma when I stuck my nose directly over the carboy mouth at the end of siphoning and when dumpping the yeast out. I attributed this aroma to CO2, lots of yeast, and hop trub. The same aroma was not in the conditioned bottles.

Gently invert the bottles a few times to resuspend the yeast and condition a about 72°, if you are not already. Give them two more weeks to see if there is a flavor change.

My bottle conditioning is at 66°. I'll be opening a bottle of amber ale in a few minutes to check the priming sugar/carbonation level before I bottle another one. This one was bottled on 9/27/13. Usually my conditioning take up to 6 weeks at this low of temperature. I'm in no hurry though. I have enough on hand that is ready.

 

[Nelrock]

I got big enough tubs that I keep the water line as high as the level of the fermenter. I'll drop the temp next batch a bit.
Bottle conditioning...I have a hall closet that I keep a thermometer in. I keep the house 70-73F. When I check the thermometer it's usually 68-69F. About once a week I give the bottles a quick spin.
I just cracked a caribou and a hefe...in the 3 weeks since I first cracked one...it's gotten significantly better. Still a bit stronger than I'd like. Prolly another few weeks.

 

[solbes]

How big of a starter did you make? Generally a starter of 2 quarts at 1.035 and letting it ferment out is a good spot for most sub 1.05 OG beers. 3 quarts for up to 1.065 or so. Also do you aerate the wort prior to pitching the yeast?

Pitching at 70 is okay, I would shoot for 60-62 for most ale strains and then maintaining low 60's for the first 48-72 hrs. Hefe would be warmer though after the first 48 hrs.

 

[Nelrock]

I used 1qt starters on the 2 I made starters for.
Considering I got similar results as the non...I'm not sure it helped.

 

[BlackGoat]

1 qt really isn't enough for a 5 gallon batch, step that up to about 2L and it might help quite a bit

 

[duboman]

This scenario sounds related to not properly pitching and controlling your fermentation temperatures, developing stressed yeast that is not properly cleaning itself up in it's final phase in a timely manner.

Use a calculator such as http://www.yeastcalc.com or http://www.mrmalty.com to ensure you are pitching the proper amount of yeast. For liquid, learn how to make proper starters and for dry yeast be sure to rehydrate properly

Ideally you pitch the yeast slightly colder than the desired fermentation temperature and allow to self rise to the desired temp. This creates a slow, controlled growth phase of healthy yeast

Try and bring your fermentation temperatures down a bit to the mid 60s for most ales. Do not rush the beer and allow it time to cleanup and drop bright (Clear) after final gravity is verified.

 

[solbes]

I used 1qt starters on the 2 I made starters for.
Considering I got similar results as the non...I'm not sure it helped.

Most liquid yeast packages say they offer professional level pitching rates into 5 gallon beers. Much study and research has been done on the topic (I highly recommend Palmer's How to Brew book, Jamil's Mr Malty calculator, and many more sources). Although you can make beer this way, upping the pitching rate and aerating the wort can offer improved results.

The research indicates that yeast need proper cell counts to do a clean ferment. Excessive yeast reproduction early on in the fermentation can lead to more byproducts that require more time to clean up. If you pitch a proper level of yeast, the reproduction required is optimized. The beer should not taste "green" after a few weeks of primary fermentation.

IMO a 1 quart starter will not create enough yeast reproduction within the starter. In fact it might not stimulate any reproduction at all, in which case you are adding a step without getting the benefit. Dry yeast packages have yeast in an optimal health condition, and would probably have more viable yeast cells than a vial of liquid yeast or a vial of liquid yeast/1 quart starter. But you can get many more varieties in liquid yeast, so there will always be a place for them.

Professional brewers are usually a step or two above us in the yeast pitch. Because they always have access to large amounts of yeast from previous batches, they pitch much higher yeast cell counts. This helps them go from grain to packaging in a much quicker fashion as their business requires.

 

[JuanMoore]

I see someone asked above about aeration, but didn't see an answer. Proper oxygenation is much more critical for liquid yeast than it is for dry yeast. A combination of underpitching and inadequate oxygenation would certainly create some off flavors that would need a lot longer to age out.

 

[Nelrock]

Appreciate all the pointers.
I make a point to aerate the wort well prior to yeast pitch.
Sounds like my starter was insufficient. Next batch...I'll correct that. Hopefully that solves the problem.