What happens if I boil too long?

[Ckilner]

On the brew I'm on now, I over estimated the boil off volume so I've ended up with too much volume and therefore a lower gravity. The bittering hops went after 30 mins and I put the irish moss in too (10 mins before the end if I'd stuck with a 90 min boil) but have not yet added the aroma hops. I need to boil off another two litres so I reckon maybe another hour. So in total the boil will be 150 mins instead of 90.
Will this do any harm?

 

[Yob]

You'll get extra bitterness, you're effectively turning your 30 min into a 90 min, you may need to add in your 30 min addition again... and then some..

You'll get a bit of extra color too, I quite like an extended boil for this..

 

[Parks]

You'll get extra bitterness, you're effectively turning your 30 min into a 90 min, you may need to add in your 30 min addition again... and then some..

You'll get a bit of extra color too, I quite like an extended boil for this..

I think you misread Yob. Looks like it's his 60min addition he's worried about and if you turn 60min into 120min it will make little difference.

 

[Yob]

indeed I did..

feckin maths... 90 - 30 = 60

My color comment remains valid

Carry on

 

[Parks]

My color comment remains valid

Yep, this was definitely valid so I didn't say anything

I was also going to say kudos on being 30min into the boil stage this early in the day but looks like Ckilner is in the UK.

 

[manticle]

I have read that bittering hops can change character if boiled for much more than 120. I think it's in the barley wine book in the classic beer styles series. Will check but either way 90 mins will be fine.

Woops - just saw yours will be 150. Is that 150 with hops in?

 

[TheCarbinator]

You were brewing at 5:30 am?
Super keen!

 

[Judanero]

So if you put your bittering addition in at 60 mins, you can boil for two hours and the bitterness will be roughly the same as if it were just a 60 min boil?

 

[manticle]

There is a finite amount of alpha acid available to be isomerised. You will get an increase between 60 and 90 but it's minor - much less significant than the difference between 60 and 30 for example.

If you boil too long, I believe you can degrade those bittering acids - as I mentioned, I'll try and remember to check that reference when I'm home and see if I can find other info that backs it up.

 

[GrumpyPaul]

You were brewing at 5:30 am?
Super keen!

I believe he is in the UK - so it's 8.30pm yesterday over there.

(my complusive urge to google things made me do the time conversion....I just cant help it, its and addiction. Google is God, and knows everything)