Backset - what exactly is it?

[cnk]

Hiya
Can someone tell me exactly what backset is? Am I right in thinking that this is the lower end of the distillation run i.e about 20%abv?
I want to try Odin's cornflakes whisky, but want to make sure I am going to do it right.
Thank you.

[OtisT]

Simply put, Backset is what remains in the boiler after a stripping run. If you are making rum, the backset it is called Dunder.

Otis

[fizzix]

Backset is the liquid left over in the boiler pot after a distillation. For rum, it's called "dunder."
Backset is used to make a "sour."
For a real life application, check out UJSSM.

Hey Otis, you beat me!

[cnk]

Thank you Otis and fizzix. That makes it really clear now, but leads me to another question. If I save the backset from this run and then use it in the next fermentation, can I mix (blend?) the two whiskies or should I keep them separate?

[Expat]

You can mix/blend any results so long as you enjoy it

[OtisT]

+1 to the comment “if you like it, it’s good.”

That said, my personal preference is to use whiskey backset with a whiskey ferment, and rum dunder with a rum ferment, and rarely do I cross the two. Also, I will often use backset from one whiskey recipe with a different whiskey recipe ferment, though I may not mix the two recipies if the backset came from a funky recipe (high ester, peated, etc) and the new whiskey is something subtle.

Otis

[Single Malt Yinzer]

All of these are similar. Initially used to reduce pH for mashing/fermentation. The secondary effect on flavor was a bonus.
https://homedistiller.org/wiki/index.php/Backset" onclick="window.open(this.href);return false;" rel="nofollow
https://homedistiller.org/wiki/index.php/Sour_Mash" onclick="window.open(this.href);return false;" rel="nofollow
https://homedistiller.org/wiki/index.php/Dunder" onclick="window.open(this.href);return false;" rel="nofollow
https://homedistiller.org/wiki/index.php/Muck_pit" onclick="window.open(this.href);return false;" rel="nofollow

[Twisted Brick]

You may also see backset referred to as 'setback' (sic), 'backins', and 'hotslops'.

Benefits of using backset is the ease of dissolving sugar, to create consistency taste-wise in successive batches, and to naturally lower pH into a more yeast-friendly range. Odin says backset is a source of valuable nutrients for the next ferment.

When using gluco for conversion in my home-malted wheat bourbons, I add a gallon (or so) of cold backset from the fridge to help drop my corn temp for my smaller grains and adjust the pH into ideal range for SEB-amyl. Some say to use 25% backset in their mashes, while others (me included) use way less (10-15%). This is because I have noticed that after 3 or 4 successive batches the backset pH gradually drops lower and lower, requiring I use less of it to sour the next batch.