Adding cool water to wort

[waynethetrain]

Most partial mash or extract recipes I find advise to do a boil with only 2 or 3 gallons of water and top it off at the end with cool water to make 5 gallons. However, they don't necessarily say to boil or take any steps to sterilize this water. From a contamination/infection standpoint, is it safe to mix unboiled, cool water into your already cooled wort?

Is it better to just doing a full boil?

 

[corvax13]

For the most part, yes, but it all depends on your water source. I brew with store bought spring water gallons exclusively, as water where I am is terrible. I just throw 2 or 3 of those in the fridge a few hours before I brew. This also helps with cooling down the wort so its at good pitching temps.

 

[ChshreCat]

I always use bottled drinking water for my top up water, but you can boil and cool tap water if your tap water is good enough for brewing in general. I put my bottled water in the fridge as well to help with cooling to pitching temps.

 

[Joker]

If you do the full boil you will need an immersion chiller or some other means of cooling.