brewing 5gal on a 10gal system
 

I'm upgrading to a 10gallon all grain system. But I have the materials to brew 5 gallons. Really my only concern is the mash tun. They are the Rubbermaid coolers. Should I stick with my 5 gallon mash tun or can I use my new 10gal to brew 5gal?

I used a 10 gallon cooler to make five gallon batches for years. No worries.