Top off Water Prep

Searched and didn't find a definitive answer. Granted, my search skills may not be the best.

If I'm doing a partial-boil, do I need to also boil my top-off water? I have been boiling my top-off as well and letting it cool several hours before brewing. Didn't know if this is actually beneficial or not.

I am on municipal water with a whole-house softener/chlorine remover.

When I did partial boils I always topped off with tap water, never had a problem. If you want to go a step further, just buy 3 gallons of drinking water to top off.

I've never bothered boiling the top-off water. Furthermore, boiling removes oxygen from the water. Yeast need that oxygen, so if you do boil the top-off water it's a good idea to aerate it, either before or after mixing it in with the wort. Easiest way to do that is to dump the water into the wort in a rough manner--not gently. Or, a funnel can be effective too. However, it could be argued that this process cancels the sterilization benefit of boiling the water to begin with. Hence, I don't bother and use water straight from the tap.

With the whole-house water softener you generally can bypass the system by using cold water. Every system I've seen so far is rigged that way.

It's a good idea to boil the water, and you definitely should let it cool before you pour it in. I would say that you won't be cancelling the benefits of boiling as long as you make sure to sanitize the funnel first.

I never boiled top off water, but I never had a water softener. My thinking is that you shouldn't have to boil- but you should bypass the softener. I'm not really familiar with water softeners, but my understanding is that hard tapwater has lots of dissolved Calcium Carbonate and Magnesium Carbonate
in it. So there's Ca++ Mg++ and CO3-- ions floating around.

Now, the water softener replaces Ca++ and Mg++ ions with sodium (Na+) ions. This is the same as if you dissolved a whole lot of baking soda in your water. I don't think this would be desirable for brewing water- I'd suggest either buying spring water from the grocery store, or bypassing the softener.

..same here... top-off right from the tap and it's never been a problem.