Adding Extract

I’m really new to homebrewing, and so far am enjoying myself very much! I’m sort of a WHY kind of guy, and one thing has really been bugging me.
I’m not into all grain yet – baby steps.
In extract brewing recipes, some of them call for all of the extract at the beginning of the boil, while some call for adding give or take about half of the extract closer to the end of the boil – seems like about 10-15 minutes before the end.
Exactly what is the purpose of this – what kind of difference does this make in the final product, and exactly why does it make this difference?
Thanks in advance

I don’t know if this is the reason behind the instructions in some extract kits but, I’ve always been told to hold off on the extracts until near the end of the boil for better hop utilization. Well, on bigger beers anyhow. It could also be to prevent over darkening of the wort for the paticular style?

Thanks for the response.
I have read that some suggest you add at least some extract at the beginning of the boil to actually aid in hop utilization because it lowers the pH slightly.
I guess also, the longer you boil the extract, the darker it will become – that makes since.
(I’ve been thinking about this since I first posted) I would also speculate that if you add the extract towards the end of the boil, if you bring it to a boil, but don’t let it go to a hard break, then you would get your wort sterilized, but the proteins would not break down as completely, resulting in more mouth-feel maybe.
Just think’in out loud.
Any of this make sense?

That sounds good to me; however, I don’t know if there is any science to back it up. It would seem there might be a haze problem if the extract isn’t boiled hard enough.

It’s been my experience that I prefer all the extract up front. Some say the sugars carmelize and therefore darken the brew so they try to minimize that by the late addition. My tests have showed the color remains about the same, not noticably lighter and ends up with less mouthfeel. Plus, I’m under the belief that more malts and more time for the hops to play with = better hop utilization. Welcome to the obsession!
:cheers: