Malt Extract Beer Question?!
Answers: I am getting ready to brew a malt extract beer but have a few questions. In the recipe it says to boil 3 gallons of water then add the extract. Once all the boiling is done I'm supposed to pour the wort into about 2.5 gallons of cold water then let ferment. Is this because its easier to boil 3 gallons of water instead of 5? Can I just boil about 5.5 gallons of water then add my extract so everything will be sanitized or will that effect the taste of my beer?
If you're not adding hops, you don't really need to boil the extract at all.
You can bring the water to a boil, add the extract to it (sort of like pasteurization) mix it well and put it into the cold (previously boiled if you want) water in your fermenter.
By mixing with the cold water, you'll be ready to pitch your yeast sooner, which will aid your sanitation efforts by shortening your danger zone time.
I find also that it's better not to boil than to boil in half the water because the syrupy not-fully diluted malt extract has a tendency to caramelize and add not-great flavors to the beer.
The addition of the 2.5 gallons of cold water is to cool down the boiled water in a quicker manner. Follow your brew recipe exactly as it is printed. If you do not follow the recipe as written, you may not only effect the taste, but whether it ferments at all.
You can boil the full 5 gallons, but it is not necessary with extract brewing. There are a couple reasons for this. First, as you guessed, it's easier to boil 3 gallons than 5, second, if you add the hot wort to the cold water in your fermenter, it's cool enough to pitch the yeast faster.
It takes a lot less time to boil half the water than to boil it all and most beginning brewers don't have a pot that will take five gallons of water, a couple of cans of extract, and (maybe) specialty grains, adjuncts, Irish moss etc. If you've ever had a boil-over from a too-full kettle, you will not forget the experience. To be safe, you can boil the extra 2.5 gallons the day before and refrigerate it but most public water supplies are safe to use unboiled if the chlorine content is not too high. Adding cold water also speeds the cooldown, so you can pitch the yeast more quickly, minimizing the chance for contamination.