kettle question

I am looking to make the change to all grain and I had a couple questions about vessels.

1. If I only plan on making 5 and 10 gallon batches will 15 gallons vessels be big enough for the bk/hlt/mlt or should i go bigger?

2. can i boil a 5 gallon batch in a 20 gallon blichmann boilermaker or will the kettle be too big for that amount of liquid?

any help is greatly appreciated!

 

15 gallon vessels would be fine for these batch sizes. I use converted kegs (15.5 gallons) and for my ten gallon batches, I start out with ~12.5 gallons in the BK.

You can boil a 5 gallon batch in a 20 gallon pot. The only issue I could see affecting this case would be whether the thermometer was placed low enough to read the temp of the 5 gallon batch since it would only fill 1/4 of the pot. From the pictures, it looks close. Maybe somebody who uses one could chime in about this.

 

I would also think your boil off would be pretty large.