4 gallon batch with smaller boil

This may have been covered plenty of times before, but my search-fu is failing me.

I am new to brewing and wanted to step my game up from the Mr. Beer to working with Extract brewing. The only things I am not clear on is if I can boil a smaller amount of water, due to pot size restrictions?
Essentially what I am looking to do it make a 4 gallon batch, but figure out how much water I would need to boil. Would buying the ingredients for a 4 gallon batch and then boiling in 2 gallons of water work out for me? So boil 2 gallons of water for all the extract and hops adding and then add 2 gallons of water to it in the fermentor?

Yes, it can work. But IMO partial boils are inferior to full.

Some people argue the about hop utilization being better in full boils over partials but I've never noticed a difference.

Also "In a partial boil, you can tend to have a "cooked extract" taste due to the maillard reactions (similar to caramelization). The wort will also darken. One way to counteract that if you have to do a small boil is to add the majority of the extract late in the boil, or even at flame out. That will leave it lighter colored, and with less maillard reactions." - Yooper

Remember too that you'll have to account for 1 gallon of boil off at least for a 60 minute boil. So, to get 4 gallons of beer (2 gallons boiled water + 2 gallons tap or bottled water), you'll need to be able to boil 3 gallons of water and watch for boil overs!

The Mr Beer to extract set can be a fun one. Partial boils do work if that is what you have to work with. Have you considered doing 1 gallon all grains? Brooklyn Brewery has a bunch of 1 gallon all grain kits you can do with a 2 gallon pot and a fine mesh strainer. Also you can do Brew In A Bag set ups. I did what you are saying and I made some decent brew, but when I switched to all grain the taste was significantly better ever since. Hope this helped

-BBS

http://store.brooklynbrewery.com/beer-making-kit-hindy-s-brown-ale

OP - it'll work just fine, been doing it that way for years. Full boils seem to be the preference, but not all of us have the space or equipment to pull them off. Partial boils and topping up will make very good beer. Just read up on late additions of the extract, maybe doing some steeping of specialty grains and adding additional hops throughout the boil. The sky is the limit.

Cheers!

Ok this is all very interesting. Well in my quest here at home in pulling equipment together I have found that my pot will only boil 1.5 gallons safely.

Now from what I am being told here this is no way I can do that because I would only end up with .5 gallons left... To the store to pick up a bigger pot, might as well get one that can do bigger boils!

Thanks all!