Backset

[Distillingchris]

When doing a sour mash, and people talk about using the 25% backseat, could someone explain it in simple terms please, if I do a 20litre batch, would It mean I could only use 15 litres then tip the rest into new wash?
Or is it just what's on the bottom, is it called the lees? The slop? That you want to transfer.
Thanks

[scarecrow]

chaslam07,

Backset is what is left in the boiler after doing a run of wash.
It has a low pH (about 3.5 - 4.5). If you add too much back into your next ferment, it will drop the pH too low and it may stall, or worse, not even start.

With sour mashing, you can add between 10% and 30%.

I usually add backset until the pH drop to 4.0 - 4.5.

scarecrow

[Distillingchris]

Is it just the liquid or the grain if doing all grain ? Do you want the stuff that's sunk and stuck to the bottom after its cleared.

[scarecrow]

Backset is what is left in the boiler

You are confusing your fermenter with your boiler.

Backset is a liquid.

The liquid from your fermenter is called the wash.

scarecrow

[Distillingchris]

So have I done a sour mash inadvertently by putting the grain out of my all grain wash into a new fermenter with sugar?

[scarecrow]

If you only used grains in your fermenter and distilled that wash, it is an all grain product.

If you have malted grains (barley malt, rye malt etc) with sugar it is called a thin mash.

If you have non malted grains (eg pearl barley, cracked corn or wheat) you have a flavoured sugar wash.

What you have done, by adding sugar to the spent grains is a flavoured sugar wash. Google UJSSM.

If you strain the grains out (after the conversion at the start) and add sugar to the strained liquid it is a thin mash.

You can only have a sour mash by adding backset. No backset, no sour mash. Sour mashing refers to the process, not the flavour.

scarecrow