# Boil down to 5 gal. or top off the water?

Im sure this has been asked before but I wasn’t able to find it on the forum.
All of the recipes for all-grain brewing show a starting amount of 7-7.5 gal. of water and then ultimately boil down to 5-5.5 gal of wort, yet extract brews have you topping off the amount to get to 5 gal. I know there are lots of variables involved but bear with me. If we assume that you are able to extract 1oz of sugar,color,favors etc(these numbers are for example ONLY) per pound of grain in your mash, and you have 10lbs in your grain bill, that would mean 10oz of sugar,color,flavor,etc in your water. Boiling it down to 5 gallons still leaves you with 10oz of ‘stuff’ in suspension, just a more dense suspension. Adding more water to it would leave you with the same 10oz of ‘stuff’ in more of a dilute state.
My question is, then, why do I need to start with 7.5gal of water? Couldnt I start with 3-4 gal, mash, sparge, boil, and then top off the water afterward?
Im really not trying to re-invent the wheel and I certainly don’t want to sound like I’m challenging common practice, but it just seems to me that there could be an easier way.

Roland

[quote=“Roland_deschain”]Im sure this has been asked before but I wasn’t able to find it on the forum.
All of the recipes for all-grain brewing show a starting amount of 7-7.5 gal. of water and then ultimately boil down to 5-5.5 gal of wort, yet extract brews have you topping off the amount to get to 5 gal. I know there are lots of variables involved but bear with me. If we assume that you are able to extract 1oz of sugar,color,favors etc(these numbers are for example ONLY) per pound of grain in your mash, and you have 10lbs in your grain bill, that would mean 10oz of sugar,color,flavor,etc in your water. Boiling it down to 5 gallons still leaves you with 10oz of ‘stuff’ in suspension, just a more dense suspension. Adding more water to it would leave you with the same 10oz of ‘stuff’ in more of a dilute state.
My question is, then, why do I need to start with 7.5gal of water? Couldnt I start with 3-4 gal, mash, sparge, boil, and then top off the water afterward?
Im really not trying to re-invent the wheel and I certainly don’t want to sound like I’m challenging common practice, but it just seems to me that there could be an easier way.

Roland[/quote]

You could certainly do that. I did it that way before I had a large enough kettle. The downside is that your efficiency will suffer and you’ll need to use more grain.