Unaged spirit changing character in bottle.

[Rebellion Rum Co]

He have some unaged rum that is lightly oaked, then some caramel added (just burnt sugar) which goes out the door cheaply.

We have noticed an astringent aftertaste that develops AFTER bottling. The start on the palate is good, but has a terrible finish that wasn't there on the day of packaging. We had one customer who bought some back from a batch and their flavour had developed enormously (within 2 weeks) compared to the bottles left in the store. All 6 of their bottles had the same character, but the bottles we had here had far less, though still some, of the offensive flavour.

I would describe it as reminiscent of what I understand ethyl acetate to taste like - kind of green applely, nail polishy, but not in any way thats good. Now that I am on the hunt for it I can detect it slightly in new distillate.

Has anyone else had any similar issues and if so what did you do to troubleshoot it? 

[Kindred Spirits]

Do you rest your rum after proofing but prior to bottling it?

 

Most spirits continue to "meld" after being proofed down or having any other additions added to it.  The rest gives it time for the water to interact wit all of the other chemicals in the spirit and develop into the final product.

[Rebellion Rum Co]

We probably let that one rest for 1 to 3 days afterwards. Mostly to let the caramel meld in.

The flavour seems to start appearing after about 2 weeks in the bottle though. I have a new batch im running today which uses a new source of molasses, no dunder, and no feints from previous runs. I'll see if that still has the issue then it might be the recipe or some other part of the process.

[Kindred Spirits]

I typically recommend 5 weeks to let Gin sit before bottling, and 2-3 weeks for rum. Its amazing how much the taste changes.

[jocko]

Kindred, how much headspace in your storage vessel during the 5 weeks on gin?

[Up&Adam]

8 hours ago, jocko said:

Kindred, how much headspace in your storage vessel during the 5 weeks on gin?

I would be interested to side by side a batch rested with 15-20% headspace and somewhere around 5% headspace. I wonder if it would pop on sensory panel or if it would take GCMS to see a difference, we let our Gin rest for 3-4 weeks before release with varying head space. It seems like more head space would allow for more volatiles to escape, especially during proofing while the exothermic reaction is still occurring. Interesting thought.

[Kindred Spirits]

I typically would have around 10% headspace and I would pull the lids a couple times during the process to take samples of how the taste has changed.