Bitterness in watered brew

[Simon David kelly]

Hi All,

I made a mini brew on the weekend (just aiming for 9 litres) but due to an extra litre boiling off and loosing a very large 3 litres due to a massive amount of crap in the bottom of the kettle (my BIAB bag is letting a lot of crap out) I ended up with just 5 litres. So I topped up with a couple of litres of water, which put the OG at 1.045 with 7 litres.

Will the addition of the 2 litres of water soften the bitterness as well as pulling the OG down?

Cheers

Si

[JackoNZ]

Hey Simon, I asked the same question yesterday after coming up short on my brew. Denim replied and from what I understood, if you hit your numbers pre-boil and lost volume to trub then your IBUs remain unchanged, makes sense as you basically didn't get all the clear wort out the pot. If you failed to get your pre-boil volume correct then you would have boiled your hops in less wort and upped the IBUs.

I'm sure DenimGlen or someone will clarify or correct if that's wrong.

Just realised I never actually answered your question in full! I'd also be keen to hear an answer ref the bitterness changing on adding water post boil.

[Simon David kelly]

That's the big question ... I'm sure I was within a 100ml of the required boil volume, so it's basically just a question of whether bitterness is diluted in the same way the grvity was.

[Simon David kelly]

Actually, saying that I wounder if the extra litre of loss in the boil would have an affect too?

[denimglen]

Diluting your wort will also dilute your IBU. I'd say you should still have the same IBU:OG ratio as your pre-diluted wort.

The extra loss of boil off will have a slight affect as the wort is slowly becoming more concentrated so you're not getting as efficient isomerisation - but the change would be negligible.

[Simon David kelly]

Nice not know .... I had fears of a real disaster there ... which would have made two weekends on the trot :o)