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I have noticed this with some of my runs when almost always using commercial and not wild yeast while making rum.

With a spoon, the distillate smells first pleasantly of butterscotch - then out of nowhere, strangely of ammonia, chemicals, and then returns to pleasant molasses-esque aromas. This would suggest there is some sort of severe contaminant throughout the general hearts portion. To the date I have never been able to determine what this is or how it is produced and it drives me crazy! Considering I usually run rums completely clear and am not known to spam nutrients this smell is entirely beyond me.

Oy vey.

what's yer recipe?

Is this just a smell during distillation or is the smell still present after airing the collection jars for 24 - 48 hours...??? It could be just about any funk that comes off at a specific temperature combined with a specific alcohol content in the boiler...

my rums smell and taste crappy for about a month then they transform into something drinkable

rad14701 wrote:Is this just a smell during distillation or is the smell still present after airing the collection jars for 24 - 48 hours...??? It could be just about any funk that comes off at a specific temperature combined with a specific alcohol content in the boiler...

That's what I suspected Rad. My thinking is that it could be, despite low yeast content, a byproduct of the high nitrogen requirements of molasses-raised yeast strains (e.g. commercial baking yeast). I do let all of rums go extended malolactic ferment so this could be a cause due to autoylsis and subsequent consumption by MLF bacteria. The copper could be breaking down various organic and inorganic ammonia compounds which cause free ammonia in the distillate, and it would air off after a few days. I'll get back to you on that.

I have never scorched a mash or wash before so I'm unable to tell what scorched yeast would smell like; otherwise I could disregard that as a potential factor.

The smell is still somewhat there. I did use a pH Buffer to lock the pH at roughly 4.9. This buffer contains some basic compounds, such as calcium magnesium tetrahydroxide... I realize that I may have inadvertently reduced diammonium phosphate to ammonia which caused the issue. I could have also scorched it as I re-ad molasses to my second distillation, but usually I agitate the wash as it is heating. I also didn't notice this weird aroma in the first distillation.

This kind of stuff always ends up being a headache!

if you have ammonia/ too much fertilazer in your wash it usually will corrode the copper and you will end up with blue distillate

MDH,

Tell me about your fermentation. What yeast? How much yeast? What temp? What sg? How long did it ferment?

Diacetyl will impart a flavor of butter/butter scotch. It is produce during fermentation. If you can tell me about your process I might be able to give you some advice.

3kg Blackstrap Molasses (Brix -> Sugar by weight is around 67%).
1 Tsp Malic Acid
WYEAST Ringwood Ale 2l Starter
3 Tsp Nutrient Blend (custom made - Autoylsed yeast, Diammonium Phosphate, Magnesium Ascorbate)
1 Tbsp pH Buffer (4.9)
Lactic Acid Bacteria
22l Dechlorinated Water

Fermented at 21c for around two weeks to allowed an extended malolactic fermentation.

This is fairly typical and I don't often encounter issues but every once in a while an issue like this pops up. I had a Kiwi Mash once which had this bizzare chemical smell to an extreme and was impossible to remove. As stated before, I also never encounter this when I use fresh sugar cane as a wild yeast source.

Well I don't see anything that remotely looks like a smoking gun. I still think this sounds like diacetyl. Normally, I would think that the yeast would reabsorb it given the extended rest you gave it.

I am curious... What's the Lactic Acid Bacteria for?

It might be possible that the lactic acid bacteria combined with your 4.9 buffer are the source of your problem. A lactic acid bacteria spoilage can occur when ph levels are above 3.5. Some of the outcomes match what you have described.

Here is an article I came accross, it describes the problem as it occurs in wine but I believe it would also apply to molasses fermentation.


http://www.extension.iastate.edu/wine/l ... e-spoilage" onclick="window.open(this.href);return false;" rel="nofollow