What is this off-flavor?

I just popped a Strawberry blonde and it has this flavor that is reminiscent of Dry Erase Markers. Slightly fruity, but solvent like with slight astringency.

Grain Bill...
2# Extra Light DME
0.5# Crystal 20L
0.5# G. Honey Malt
6# Rahr 2-row US
2# Light Wheat Malt

Mini-mashed grains, mashed at 150 degrees for 60min. Eff was only about 68% and pitched it a bit warm because I got rushed. Used Safale05. Quickly got it down in the 68 degrees range using swamp cooler and fermented 7 days, then racked onto 3# cleaned, chopped strawberries and finished for 14 days before bottling. Was in the bottle about 4 weeks before tasting. I definitely get more Wit/Weizen flavor than I expected in this beer with a wheaty spiciness. The solvent aftertaste though is what really makes you want to stop drinking it.

Looking at John Palmer's off flavor discussion I see

Astringent
Astringency differs from bitterness by having a puckering quality, like sucking on a tea bag. It is dry, kind of powdery and is often the result of steeping grains too long or when the pH of the mash exceeds the range of 5.2 - 5.6. Oversparging the mash or using water that is too hot are common causes for exceeding the mash pH range. It can also be caused by over-hopping during either the bittering or finishing stages. Bacterial infections can also cause astringency, i.e. vinegar tones from aceto bacteria.

The brown scum that forms during fermentation and clings to the side of the fermentor is intensely bitter and if it is stirred back into the beer it will cause very astringent tastes. The scum should be removed from the beer, either by letting it cling undisturbed to the sides of an oversize fermentor, or by skimming it off the krausen, or blowing off the krausen itself from a 5 gallon carboy. I have never had any problems by simply letting it cling to the sides of the fermentor.

Solvent-like
This group of flavors is very similar to the alcohol and ester flavors, but are harsher to the tongue. These flavors often result from a combination of high fermentation temperatures and oxidation. They can also be leached from cheap plastic brewing equipment or if PVC tubing is used as a lautering manifold material. The solvents in some plastics like PVC can be leached by high temperatures.

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No apparent infections, no plastic, and I used a blowoff. Not sure where it would have oxidized as it's not very old and I try to avoid too much HSA. Actually sparged too low (160ish) instead of too hot and there'es virtually no hops in it. I did pitch it hot (maybe 80-85), but it should have been down to 66-68 degrees within 4 hours in fermentor. One thing that may be an issue is I used a pool strip which said my water is Ph 7.5-8.5 so I have since stopped mashes until I can get a water report and see if I need to modify my water. If anyone has experience with such a flavor and can provide feedback on what the flavor is and what caused it I would appreciate it.

I've heard of old extract causing ball point pen flavors....

Water chemistry, maybe chlorophenols?

wyzazz said:

Water chemistry, maybe chlorophenols?

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Don't think this is it since I don't use bleach during any of my process and we have well water with zero chlorine.

Do you have a softener?

I'd say it is due to the fermentation. It's probably a combination of phenolic and fusel characteristics all caused by the yeast, temperature of fermentation, oxygen in the wort, and pitch rate. Phenolic aromas can be a characteristic of the belgian yeast. Some is okay but can easily get out of hand. Fusels are a solvent like aroma caused by any of these or any combination of these: too high of a fermentation temperature, not enough oxygen in wort, under pitching.

wyzazz said:

Do you have a softener?

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No, we have a whole house dual tank aeration and carbon filtration system.

jmo88 said:

I'd say it is due to the fermentation. It's probably a combination of phenolic and fusel characteristics all caused by the yeast, temperature of fermentation, oxygen in the wort, and pitch rate. Phenolic aromas can be a characteristic of the belgian yeast. Some is okay but can easily get out of hand. Fusels are a solvent like aroma caused by any of these or any combination of these: too high of a fermentation temperature, not enough oxygen in wort, under pitching.

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What is most likely the procedure problem here? I rehydrated the S-05 in a cup of water, but have mostly read that dry doesn't require a starter. This is supposed to be a clean american yeast similar to Chico. The fermentation temp was about 68 degrees which is well within the temp range. Could simply pitching high be enough to cause off flavors to this extreme when I got it down to fermentation temp pretty quickly?

As for the oxidation, I can't get a straight answer on this. I try to be gentle with the wort when moving it over 80 degrees, but for every person saying watch HSA there's 2 that say it's not really a problem. Also, nothing with this procedure should be too much different than other brews that don't have this flavor in it.

Seems like the strawberries are a likely source of off-flavors

HiGravShawn said:

What is most likely the procedure problem here? I rehydrated the S-05 in a cup of water, but have mostly read that dry doesn't require a starter. This is supposed to be a clean american yeast similar to Chico. The fermentation temp was about 68 degrees which is well within the temp range. Could simply pitching high be enough to cause off flavors to this extreme when I got it down to fermentation temp pretty quickly?

As for the oxidation, I can't get a straight answer on this. I try to be gentle with the wort when moving it over 80 degrees, but for every person saying watch HSA there's 2 that say it's not really a problem. Also, nothing with this procedure should be too much different than other brews that don't have this flavor in it.

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I misread your post. Somehow thought you were using a belgian yeast. Go figure. Someone else mentioned the strawberries as the culprit. That sounds reasonable as the fruit might be producing hotter fusel alcohols.

jmo88 said:

I misread your post. Somehow thought you were using a belgian yeast. Go figure. Someone else mentioned the strawberries as the culprit. That sounds reasonable as the fruit might be producing hotter fusel alcohols.

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I really think it must have been something with the strawberries as this was sort of quiet simple brew day with nothing odd and yet this intense flavor is present.