Is a yeast-starter without temperature control worse than no yeast-starter at all?

Question

EDIT: Crap, it appears I mislead myself. Northern Brewer includes a temperature range of the particular Wyeast you are using, and I assumed this temperature range factored out off-flavors. I read on this stackexchange that it is a good idea to let the temperatures rise after the initial 3-5 days of fermentation. I assumed this meant to the top of the temperature range specified by NB/Wyeast. My Belgian Ale I allowed to go roughly 78*F during the day times. My Cream Ale I allowed to go specifically 71-72*F nearly round the clock. Regardless, I enjoyed this discussion and learned something about yeast starters and temperature!

I have used a yeast starter for my last 3 batches. Two of these batches are bottle conditioning for carbonation, but I took two of them out to test a few days ago.

They were so full of esters that my neighbor referred to the first one as "Bananna Beer", and the second one as "Strawberry Beer".

...

One of the batches that I am annoyed about in particular was a Belgian Trippel that took about 6 weeks (+2 weeks bottle conditioning) and required a secondary, and was the most expensive extract I've bought so far. The other batch was a creme ale that took 2 weeks (+ 2 weeks bottle conditioning).

I've never had the fruity-beer problem because I've done a fantastic job at controlling temperature with a swamp cooler.

However, I can't use a mini-swamp cooler with my yeast-starters, as my home-made stir-plate can't hang.

Questions:

1) Is fruity flavoring always and everwhere a side effect of high-temperature and ester production, or may sanitation problems also generate fruity flavoring?

2) If fruity flavoring is always and everwhere formed by high-temperatures, is it better to forgo a yeast starter if it is not possible to control the temperature of the yeast starter? I also figured that maybe a 12 hour yeast starter at night time would be better than 72 hours in higher heat.

Thank you.

Answer 1

First, unless the starter temp goes over maybe 90F, there is no damage to the yeast itself. second, for a starter of the size that you'll need for a tripel, the best course of action is to decant the spent wort before pitching so it won't have any flavor effect on your beer. remember, with a starter you're growing yeast, not making beer, and a starter generally grows better at warmer temps. Another thing to be aware of is that temp ranges listed by yeast manufacturers are based on yeast performance, not what makes the best beer. You will almost always make better beer by avoiding the higher end of the range. Even if you do use a higher temp, you should start the fermentation at a lower temp for the first few days, when the majority of esters are produced. Now to your specific questions...

1.) Ester production is not always caused by high temperatures. That's just one factor. Another is pitching rate. Contrary to what has been repeated over the years, a too high a picthing rate can lead to increased esters due to the effects of the enzyme acetyl CoA. This has been cited both by Neva Parker of White Labs as welll as Dr. Clayton Cone of Lallemand. her's a link to Dr. Cone's statement. http://www.danstaryeast.com/articles/yeast-growth Ms. Parker talks about it here in her presentation "Yeast Mythbusters", although you have to be an AHA member to access the info..http://www.homebrewersassociation.org/attachments/presentations/pdf/2012/1616-08%20Fermentation%20Mythbusters%20-%20Neva%20Parker.pdf

2.) It is absolutely NOT better to forgo a starter in higher temps. As noted above, you want to let the starter ferment to completion, then decant the spent wort. Even if that wort has a high level of esters, the yeast slurry will carry them into the beer. A 12 hour starter doesn't give you enough time for the starter to ferment out and drop the yeast so you can decant.

Answer 2

You can get esters from under-pitching as well as high temperature control, so skipping the yeast starter will be much worse than a starter without temp control, since you will be significantly underpitching.

I'm guessing the Trippel was a fairly big beer, for which you need a proportionally larger yeast starter and then some. A 1.080 beer would need a 4 liter starter (2l if on a stir-plate.) 4l is a significant part of a 5gal (19l) beer and could affect the taste of the beer, particularly a light flavored beer like a Trippel - given that starters should be fermented warm, it could easily have been a fruit-bomb. That's why it's advised not to pitch the starter wort but decant and pitch only the yeast.

While your swamp cooler may have worked well for other beers, the increased rate of fermentation for the big beer could have pushed the temperature up higher than in previous brews. Also, swamp coolers do suffer temperature swings which produce further stresses on the yeast and more esters.

Answer 3

(To echo a comment on your post…) the temperature of the starter shouldn't affect the larger batch. Please describe the temperature control of the ferment itself, plus please describe the parameters of the starter. Both fermentation temp issues and/or underpitching (which might still be the case if your starter just isn't big enough). Also, what did you do for wort oxygenation and nutrients on the Tripel?