Why add extract late [duplicate]

Question

I have heard mention of late addition of extracts. I was under the impression that you need to boil the extract to kill off any possible nasties?

When I brew, so far always from a prepackaged kit, after the steep, I get the boil going, add the steep/rinse water, bring back to boil, add liquid extract, bring back to boil, add hops, boil 60 min, add finishing hops...

what would I gain or lose by waiting to add the extract? and how late into the boil is considered a late extract addition?

Thanks and Cheers!

Answer 1

You should boil the extract to kill off any nasties. (In reality it's probably not that big of a deal, since it should theoretically already be sanitary coming from the manufacturer, especially if it's canned liquid extract)

The point of adding extract late is to prevent your wort from darkening. Boiling the extract for the full 60 minutes will cause the wort to darken somewhat, so if the color of you final product is important to you, you might consider adding all of the extract only in the last 15 minutes of the boil.

That being said, it is important to add at least some of the extract with/before your bittering hop addition. It's been shown (by others, not me) that you get significantly better hop utilization when you add part of your extract as opposed to not adding any.