TylerPederson

If you have a tank that you can put on a calibrated scale you can weigh the water and work through it that way.

One method you could use to reduce fusel oils is to double distill your whiskey, and dilute your low wines prior to the spirit run to encourage a phase separation. Diluting your low wines to 30% abv or less 24 hours prior to the spirit run will cause many of the fatty acids and heavier oils to float to the top of your holding tank. Simply draw out from the bottom of the tank, leaving the oil slick behind.

This practice is briefly covered in Whiskey: Technology, Production and Marketing. Here is a link to the pages discussing phase separation:

http://books.google.com/books?id=AwF0AwAAQBAJ&pg=PA168&lpg=PA168&dq=phase+separation+whisky&source=bl&ots=zbb73mf4LU&sig=Kb9rWmm-zp7nV4XK9L8GKzV-VbY&hl=en&sa=X&ei=7c5bVPOjKcmBiwKO5IGYCA&ved=0CCsQ6AEwAQ#v=onepage&q=phase%20separation%20whisky&f=false

I imagine that milling the malt increases the extraction of fusel oils during the distillation process, much the same way that milling increases the availability of starches during the mashing process. The milling process simply makes it more accessible. If this wasn't the case, everybody is wasting a lot of time and money on milling.

I have to concur with smoogdog here, don't leave water in them for more than a couple of days. Do not introduce sulfur to your barrels either. When we get bulk shipments of barrels that we can't use immediately, we keep them outside and turn on a sprinkler every few days to keep them from drying out. If a shipment of sherry casks arrive and the barrels appear too dry to hold liquid, we stand them up and flood the heads with water. We will let it sit until it holds the water and stops leaking from in between the stave joints. Then, flip the cask over and repeat. With a couple of our quarter casks, I was able to rehydrate them pretty quickly by submerging them in a trash can full of water for a day.

The other day I came across this article about the role of copper in distillation. It's not entirely comprehensive, but there are some interesting facts in there:

http://whiskyscience.blogspot.com/

My name is Tyler, and I am a Stillman at Westland Distillery here in Seattle. I have been lurking on this site since around 2009, and it has been a fantastic resource over the years. Now that I've officially joined the forum, I hope that I can return that favor and help keep the forward momentum going for our industry.

Cheers,

Tyler

No personal experience here, but I've read that acreolein can be produced by lactobacillus fermentations at elevated temperatures or in extended fermentations. The data I've read also suggests that after 2-3 years maturation with ethanol, those peppery-pungent off flavors will dissipate.