Grassy, vinyl flavor

[rtshfd]

We're messing around with our first rum-like product (honey and molasses) and during late heads/early hearts I'm getting this pungent grassy/vinyl flavor that's quite strong.  We're single distilling through 4 plates as close to a pot style run as possible (with as little reflux returning to the kettle as possible).  We're using blackstrap molasses, local honey at a SG of 1.074ish.  

We used a champagne style yeast from lallemand (SR), and a dose of their nutrient (GN).  I expected to be low in DAP but we fermented without supplementing.  

Has anyone had this grassy/vinyl off flavor before?  

[Silk City Distillers]

Did you rack the rum beer off the yeast?

[rtshfd]

15 minutes ago, Silk City Distillers said:

Did you rack the rum beer off the yeast?

For the most part yes, the lees were left behind.  

[MDH]

Firstly, does your source of water have any free halogens?

Secondly, have you tried any pilot batches with other yeasts?

[whaleShark]

I've done (honey + molasses-A) with MW and purified water, no noticable off-odors.

 

[Goldenjellyfish]

Could it be something from the honey or molasses?  Young rhum agricole can have a strong grassy flavor, at times bordering on solvent or diesel-like flavor.  Granted you did not start with fresh cane juice.  How much and what type of honey did you use?

I would be very interested to know the chemistry behind the flavor if anyone knows that story.

 

Best, GJ

[bluestar]

2 hours ago, Goldenjellyfish said:

How much and what type of honey did you use?

Many of the honey types are not suitable for a rum-like product, having distinct off flavors and aromas.

Don't use champagne yeast.

We've been making honey spirit for 4 years, right choice of honey and yeast can produce a wonderful spirit.

Also, when mixing honey with another sugar source in the fermenter, the results can be unexpected. We have not tried molasses. We did try agave, and we could not get that to work.

[iglomski]

Just speaking from experiences with mead making, I have run into grassy/vinyl flavors many times in my mead. It was totally dependent on the type of honey I used. I would bet a lot of those flavors could make it through the still too.

I would do some small scale test fermentations and just taste them straight before even getting the still in the process. 

 

Just my two cents.

[rtshfd]

Thank you for all the input.  I have minimal experience working with honey.  All the meads I've made have been less than desirable!

Bluestar, when you say no champagne yeast, can you speak to that?  Is the typical ester profile no good (the result is what I'm tasting?)? I did many test batches with the yeast I had on hand which was geared towards grain and it had a nice floral character.  From those batches we changed from a clover/flower honey to a buckwheat honey (seeking a more earthy profile) and the aforementioned yeast change.  

Either way, round two will have much more DAP and possibly back to our whiskey yeast.  The batch in question from the op is in barrels hopefully to temper over time.  You never know.  

[bluestar]

I have made meads with champagne yeast. None of the spirit I made from that tasted good. Just my experience. Don't use clover honey either. I never tried whiskey yeast, but I would be concerned that it would require too many nutrients.

[rtshfd]

15 hours ago, bluestar said:

I have made meads with champagne yeast. None of the spirit I made from that tasted good. Just my experience. Don't use clover honey either. I never tried whiskey yeast, but I would be concerned that it would require too many nutrients.

Nutrient was why I made the switch when scaling. Live and learn.  The batch in question is in second fill bourbon barrels and coming along nicely.  Aging really does seem like magic at times.  

[bluestar]

1 hour ago, rtshfd said:

Nutrient was why I made the switch when scaling. Live and learn.  The batch in question is in second fill bourbon barrels and coming along nicely.  Aging really does seem like magic at times.  

Yes, we have aged in second fill small bourbon barrels for 15 months.

[nabtastic]

I understand that mead requires lots of nitrogen, usually in the form of DAP... maybe a different N source would help clear it up?