Nuke Aging and Proof Drop

[Braz]

I have a newly minted batch of pumpernickel rye that I am nuke aging prior to barreling. The white whiskey after cuts measures 63% ABV but after two nuke cycles it measures 57%. I am careful to keep the temp of spirit under 160F during the microwave sessions so I don't think I am cooking off the alcohol. I don't get it.

Has anyone else experienced this drop in ABV after nuking?

[FullySilenced]

Some high end ethanols will evaporate... heat it then put the lid on tightly till it cools and goes into a vacuum state...

Just call the loss... the angels share...

happy stillin, and keep on nuking

FS

[carbohydratesn]

Doesn't matter if you are keeping it under 160, liquids do in fact evaporate below their boiling point.

[FullySilenced]

read some more... some start at 145F

FS

[Bushman]

When I use my Ultra Sonic Cleaner for flavoring/aging I leave the lid on till it cools and haven't noticed a drop in either abv or through evaporation. I do have to say that it has been mostly an eyeball thing so next time I do it I will take closer readings in both areas.

[Braz]

Thanks all. I've done the nuke thing a number of times but this is the first time I've checked the before/after proof. I do routinely cap the jars immediately and let the vacuum build. I like hearing the lids on the Ball jars pop. I will hold the peak temp down a bit on the next batch and see what happens.

[NZChris]

I thought 150f was the recommendation and that is the highest I've aimed for. My losses were never significant. I have had a microwave with a poorly aimed wave that spot heated the top of the jar, causing boiling. It went to the tip.