First time full boil

[phoneman65]

We are going to be brewing NB's ESB extract and are  planning on doing a full boil for the first time.  I was trying to find the right equipment set up for what we have but it doesn't show anything for a 7 1/2 gallon pot for extract on Beer Smith. How much water should we start with?

[Scott Ickes]

7.5 gallon boil pot is a little small for a full boil.  You're going to be starting with anywhere from 6.5 to 7.4 gallons of wort.  A boil over is almost a certainty.  With my system, I use a 15 gallon boil pot for 5 gallon batches.  It works for 10 gallon batches also.  If you can swing it financially, purchase the largest boil pot you can afford.  You can never go too big when it comes to a boil pot.

If I only had a 7.5 gallon boil pot, I'd still do a partial boil, with late dme addition.  I used to use an 8 gallon boil pot and was never able to do a full boil with it.

[phoneman65]

Thanks for the input. We should be looking into a bigger pot soon.

[Roadrocket]

+1
I also use a 15 gallon boiler for 5 gallon batches. I wouldn't want to use anything less. A 7.5 gallon pot is a bit too small.

For a 5 gallon batch I need 7.9 gallons of wort to do a 60 minute boil. I loose about 1 gallon to boil off and more than a gallon gets left in the bottom, below the tap, with the hops and break material. I put 5.5 gallons of the clearest wort into the fermentor to give me 5 gallons in the keg.

A 15 gallon boiler gives plenty of room for a good vigorous boil without the possibility of it splashing or boiling over. The wort will also expand by 4% when it's boiling.

[haerbob3]

I would use as much water as you safely can and top off.  I too use a 15 gallon kettle for the boil and mash.  This on would work well 2 Weld 9 Gallon Stainless Steel Brew Pot I have 2 of the 15 gallon ones.