Boil ?

[1AndDoneAquite1]

Why does my instructions have me boiling only 2.5 gallons then adding another 2.5 gallons of unboiled water?

 

[ThunderpantsBrewing]

That's for beginners who don't have a large enough kettle for a full boil. How big is your kettle?

 

[Psylocide]

Assuming it's an extract kit... most of those kits are set up to do a partial boil (2.5 gal) then topping off in the fermenter (probably more than 2.5 gal to account for evaporation) to get to 5 gal.

You can do a full volume boil if you want, hops will be utilized a little differently, but if you have the ability to do full volume, go for it. Helps when you go to take your OG... don't have to worry about it not being mixed well enough.

Either one will make beer.

 

[unionrdr]

Most kits are designed that way, since many folks don't have a kettle big enough to do a full boil. Partial boils are quite common. I have a 5 gallon SS kettle I started with & can do pb/pm biab in it just fine. I can boil up to 3 1/2 gallons & still have room for the foamy hot break right before the boil. Then you just strain into the fermenter & top off with cold water & stir well. then take OG sample & pitch yeast.

 

[Black Island Brewer]

For a couple of reasons. First is that the kit (I assume you're making a kit) has hops provided, and once you add your malt extract to the water, the thickness of the wort will affect how much bitterness you get from the hops. If you boiled all the water at the same time, your beer would be a bit more bitter, because of better hop utilization. Also, chilling 2.5 gallons by cooling it and adding cool water is an easy way to get the wort down to fermentation temps. If you did a full wort boil, you'd need some kind of ability to chill the wort. And finally, most beginners don't have a 6+ gallon pot to start, but many have a 4 gallon pot.