Wet dog coming from gin?

[fermentingkiwi]

Hello all!

1st post, but been a reader for many years, and absolutely love the info and feedback on this site. Kudos to you all. Now I need to ask for your help.

I have just aquired a small 2 litre alembic copper pot still.. tiny I know. Cleaned it with a vinegar run, and then a run with feints left over from when I made a neutral last year in my other larger still. I then went for a gin run, using vodka and your standard gin botanicals in quantities recommended on this site. The heads that comes out smells and tastes wonderful, but increasingly as you get close to the end I start to pick up that wet dog / cardboard horrible dank tails aroma. I would start to notice the smell in the distillate - more so when diluted - after about 1/3rd through the run, and after the first third I wont even consider keeping any more as the smell is just too strong. My (store bought) vodka doesnt have any smell, so Im wondering where it might be coming from? Contamination from distilling the feints earlier?

Interestingly, I experienced a similar problem with my other larger still which has a reflux head when I made gin previously. Tails was really wet dog like. That time I put it down to the fact I was using my own polished neutral and didnt do it as well as I should have, although the neutral smelt and tasted fairly clean before making the gin.

Botanicals used:
(Juniper, corriander seed, angelica, cinnamon, orris, lemon peel, orange peel, and black pepper)
Method: Just lump everything in the still with the vodka and fire it up. No messing about.

Any ideas what might be causing the strong danky tails aroma?

PS. Searching for this on the forum is a bit of a nightmare as "gin" is a 3 letter word and gets ignored by search. So I apologise if this topic has come up elsewhere.