Cooling partial boil with cold water

[brewinginct]

I'm brewing 3.5 gallons for a 5 gallon batch. I'm using an immersion chiller/ice bath for the boiling wort but what temperature should I shoot before I add cool water to top it off? I don't want to cool the wort too much and then add the water and end up bringing the temperature lower than I wanted for pitching the yeast.

 

[sampson0420]

around 100F depending on the temp of your cool water. Just make sure you're below 80F before pitching. I boil 3 gallons, bottle up 2 gallons and put in freezer. I usually add it to my wort after 5 minutes in the ice bath when it's around 120F. I can cool my wort to under 80F in under 15 minutes using ice bath and chilled water.

If I ever start doing full boils, I'll definitely invest in a immersion chiller.

 

[ndsgr]

I wouldn't worry about cooling too much. Maybe just me, but I never had that problem, just the opposite actually. If somehow you do cool too much, you can always wait a little while before pitching. I doubt you will get that cold though.

 

[avidhomebrewer]

I would just let it cool through your setup for about 15 minutes and you should be set to add the extra water then the yeast. I usually run my immersion chiller in 5 gallons of wort for about 20 minutes.

 

[brewinginct]

Alright based off of these replies it sounds like I should:

1) Chill with the immersion chiller for about 15 minutes

2) Add the top off water to the wort while it's still chilling in the brew pot

3) Get the wort down to pitching temp and siphon/aerate into container.

Sounds good? The other option I was considering was letting the wort chill in the brew pot all the way to pitching temp, siphon that into a spare fermentation bucket. Mix in the top off water so that it's at 5 gallons, mixing with the autosiphon. Then siphon through the aerator into the glass carboy that I will be using.

Does either option sound better than the other?

 

[NewrBrwr]

What I've been doing is keeping 2 gallons of water in the refrigerator and I take them out when I have 15 min left of the boil. I use an immersion chiller until the wort gets to around 80 degrees. I then transfer the wort to the fermenter and then add the 2 gallons of still cold water and whatever I still need to hit the 5 gallon mark I use water that's been sitting at room temp. This seems to get me to around 70-75 degrees right away which is when I pitch the yeast. Not really sure how I got to using this system but hey, it works!