Chilling wort by adding water?

We live in London, and our tap water is pretty hard. So we ordered a home water cooler, and we absolutely love it. The water comes in 19-liter bottles, so they last a while, and the cooler has both a hot and cold spigot; hot water is 95-96* C and cold water at 6-8* C.

Since the biggest pot I have only fits 10 liters or so, I've been doing 2-gallon boils with extract. I top up throughout the boil, to keep me at about 2 gallons, and add more water at the end to get me to 5 gallons.

Topping up during the boil works pretty well; if I add hot water from the cooler slowly, it doesn't affect the boil at all.

I would think that adding 2-3 gallons of 6-8* water to 2 gallons of hot wort would bring the temperature down right quick. Any reason why I would want to chill the 2 gallons of hot wort down without adding water directly?

surista said:

I would think that adding 2-3 gallons of 6-8* water to 2 gallons of hot wort would bring the temperature down right quick. Any reason why I would want to chill the 2 gallons of hot wort down without adding water directly?

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I can't do the math (well, I could but I hate math) but even 6-8 degree water won't cool 100 degree wort as fast as you think. Then you have 23 liters of too-warm 37 degree wort, and it will take forever to cool. (I speak from experience here, by the way!)

What you could do is cool the wort in an ice bath to 39-40 degrees, THEN add the cold water to bring you up to 5 gallons. That would get you to 17 degrees quickly, and that would be a perfect pitching temperature. It takes some trial and error, but once you figure out the perfect combo for you, it is quick and easy.

Hmm, good point - I hadn't thought of what would happen if the cold water didn't cool the wort enough. I obviously would be adding the wort to the fermenter with 2-3 gallons of cold water in it. It would suck to be sitting there with five gallons of too-hot wort in the fermenter....

Next time I'll start out with the ice-water-bath-in-sink method first, then add water once I've gotten the wort down to a reasonable temperature.

Txs!