Help to analyze source of off-taste

[Beernerd]

Hi all!
First off all let me say,- I am new to this forum (as a poster, I have read homebrewtalk for quite some time), I am Norwegian, and usually reside in forums from my country. So please excuse any bad english. I also mostly use the metric system, but will try to convert measures to imperial units as best i can.
The question is as follows:
A while back i brewed Biermunchers Centennial Blonde. 5 gallon, all grain.
I followed the recipe exactly, fermented at 68 degrees with Notty.
However, this brew came out horribly! A very hot, boozy, solventy taste completely dominated the beer. It was bottle conditioned, and I even left it alone for 4 months in cold storage, just to see if it would get drinkable. It did not, so I had to dump it.
My method of fermentation is as follows,- I put the fermenting bucket in my (cold) basement, in a little closet made of styrofoam. There it is wrapped in an electric blanket, witch is hooked up to a temperature controlling device (UT-200), with the sensor taped and isolated against the bucket.
This method has worked well for all my previous and later brews, it is just this particular batch that came out undrinkable.
So does anyone have any idea what could have happened?
If there is essential information about the process I forgot to mention here, just ask, and I will supply it as best I can.
Btw,- i brewed this again now, and it will be transfered from fermentation bucket to corny keg tomorrow. The sample i just took tastes great, the only alteration i did this time was swapping Notty for US-05. I normally use liquid yeast, but if the recipe calls for a clean, low ester yeast, i find that US-05's taste profile is so similar to WLP001 i wont bother with liquid yeast and starters.
I allways rehydrate when i use dry yeast.

 

[LittleBroBrews]

Sounds to me like the fermentation temps where possibly to high, it could also be that the equipment used wasn't fully cleaned and sterilized. Read below for explanations of your off flavors.

Solvent

Solvent off-flavors have a pungent, acrid aroma followed by a harsh, burning (not warming) sensation on the back of the tongue that persists in bad cases. The most common cause is from ethyl acetate wherein ethanol is esterified by acetic acid from higher temperature fermentations, though wild yeasts may also impart production of ethyl acetate. Prevention includes proper sterilization of equipment and avoidance of excessive ferment temperatures.

Boozy

Both an aroma and a mouth-feel. A hot, spicy flavor detected by the nose as a vinous aroma and by the tongue by a warming sensation in the middle of the tongue.

This is the end product from the conversion of glucose into carbon dioxide and ethyl alcohol. Other, higher alcohols called fusel oils (eg, propanol, butanol, amyl alcohol) and contribute to vinous aromas and tastes.

Fusel oil production will be a function of the yeast strain used and the fermentation temperature (higher temperatures give more fusel oils).

 

[BeerGrylls]

I would point also towards fermentation temperature first. You mentioned that your cellar with a heater and temp control. What did you have the temp control set to? I don't know if you used Danstar dry Notty, or White labs liquid WLP039. Danstar oddly doesn't have the range listed in their data sheets, but you want to go up to a maximum of ~21 degrees (70F) and that's wort temp. Realistically the way Notty works, you want to be around 18 or less (<64F) since the fermentation generates a lot of its own heat.

With a beer like a Blonde I like to stay on the low end of the yeast range, because you don't want to introduce esters either. I'd have probably set my control for around 15.5 / 16 (60-61F).

 

[B2Barleywine]

+1 On fermentation temps
fermentating wort can be 8-10f degrees above ambient. You may have been running hot and not known it. What is the ambient temp of your basement and how well insulated is your Fermenation chamber. May have been running hot in there. I just did Centennial Blonde with Noty at 68f in temp controlled freezer and it came out perfect..

 

[kombat]

Sounds like the classic characteristics of a too-hot fermentation. Notty is notoriously intolerant of higher temperatures. Keep those temperatures under control and you should be fine in the future.

 

[Trail]

Homeboy said his temp was 68f which is borderline too hot anyway. If you're shooting for 68 and temping by ambient and not wort temperature, you're in the

 

[BeerGrylls]

Homeboy said his temp was 68f which is borderline too hot anyway. If you're shooting for 68 and temping by ambient and not wort temperature, you're in the danger zone.

Oh, I just saw the 68 buried in that post. Good observation. Set at 68 doesn't take into account the interior temp of the ferment, or maybe his temp control wasn't working right.

 

[B2Barleywine]

He said he taped and isolated probe against the bucket. I'm assuming his heater was set to 68f. Under the right circumstances this can work. Problem is, the basement ambient wasn't low enough to effectively cool the wort and/or his insulated chamber didn't let enough cool in, and hot out.

 

[progmac]

nottingham in particular tastes kind of bad at 70F. S05 is much better at those temps

 

[BigFloyd]

+1 on it probably being a temp issue. Next time you use Nottingham, set the temp at 58-60*F and keep it there 4-5 days before slowly bringing it up to finish at about 66*F.

Notty is a really nice cool ferment ale yeast. I usually start it at 57*F and have tried it (successfully) as low as 55*F. It does not, however, like anything much above 68*F beer temp (not air).

 

[Trail]

He said he taped and isolated probe against the bucket.

Yep. I tape and isolate my probe against the carboy. Last brew I checked on before I went to bed, and a damn good thing too... condensation on the carboy slipped the tape.

Would have ruined the beer if it's gone overnight thinking it was the wrong temp, and my instrumentation would have shown clear skies the whole time.

 

[LittleBroBrews]

Yep. I tape and isolate my probe against the carboy. Last brew I checked on before I went to bed, and a damn good thing too... condensation on the carboy slipped the tape.

Would have ruined the beer if it's gone overnight thinking it was the wrong temp, and my instrumentation would have shown clear skies the whole time.

can you possibly to get the probe inside the vessel? As pretty sure your off flavors where generated due to high ferment temp. By getting your probe inside the vessel it will read the temp of the liquid not the side of the vessel.

By reading the side of the vessel you can be slightly higher/lower of temp than the actual liquid temp which can cause major problems.

 

[BigFloyd]

can you possibly to get the probe inside the vessel? As pretty sure your off flavors where generated due to high ferment temp. By getting your probe inside the vessel it will read the temp of the liquid not the side of the vessel.

By reading the side of the vessel you can be slightly higher/lower of temp than the actual liquid temp which can cause major problems.

Fortunately, this ^^^^ is not true. There has been more than one HBT member who simultaneously measured temps in the two places. 1) taped to side of bucket and covered with bubble wrap to insulate and 2) thermowell inside the middle of the bucket. The result? Only about a 1*F difference (warmer in the middle). Factor in the geometric concept that a higher volume of fermentation is actually going on in the the liquid around the wall of the cylindrical bucket vs. the very middle and it is pretty much a wash.

So, by taping the probe to the outside of the bucket/carboy and insulating it with bubble wrap or something, you are indeed getting an accurate reading on your fermentation temp. There's no need at all to insert a probe into your beer.

 

[Trail]

Yep. Not a significant difference, but easily accounted for all the same. I've started using a webbing-style belt to secure my thermistor and insulation to the exterior, and it works quite well.

 

[BeerGrylls]

Now it's been 4 days after the OP came asking for advice, gotten two pages of replies and discussion, and hadn't peeked his head back in? Brother are you out there?

 

[Beernerd]

Now it's been 4 days after the OP came asking for advice, gotten two pages of replies and discussion, and hadn't peeked his head back in? Brother are you out there?

Sorry, i have been busy.. But thanks for all the replies!
I agree that it must be a temperature issue, but it's the only batch that this has happened to, and i use the exact same procedure every time.
68 degrees seems high for notty, but that's what Biermunchers recipe called for.
So i guess during the most active time of fermentation, the temperature has risen above notty's comfort zone. My temp. controller isn't broken as was suggested, because i have used it like 10 times after this batch with no problems.
Anyway, i'm going to conclude with this being a temp. issue, and never use notty at those temperatures again.
Thank you all!

 

[BeerGrylls]

Sorry, i have been busy.. But thanks for all the replies!
I agree that it must be a temperature issue, but it's the only batch that this has happened to, and i use the exact same procedure every time.
68 degrees seems high for notty, but that's what Biermunchers recipe called for.
So i guess during the most active time of fermentation, the temperature has risen above notty's comfort zone. My temp. controller isn't broken as was suggested, because i have used it like 10 times after this batch with no problems.
Anyway, i'm going to conclude with this being a temp. issue, and never use notty at those temperatures again.
Thank you all!

nice .. thx and I hope the next batch turns out better