Got a keg, what to do with it....

My father in law gave me a bud keg that he had sitting in his garage for a few years. He offered, I accepted, now I'm not sure what to do with it. My current set up is all grain. Mash tun is a 10 gal rubbermaid cooler. Been doing 5.5 gal batches. I have a 10 gal brew pot currently and a bayou classic SQ14 burner. Carboy space is not an issue. What do you all think is the best way to incorporate this bad larry into my gear? Perhaps with what I have now it's not even worth it?

Fermenter, pop and orange carboy on top and ferment 13 gallons at a time if you want to. Or, you could make 15 gallons of Apfelwein! :rockin:

15 gallons of apfelwein sounds awesome......

On a side note, I got some local unpasteurized Apple Cider last year and just tried one of the bottles. It was the best batch to date!!! Maybe look in to buying some cider from a local orchard, they technically could probably press it right in to that keg after you remove the spear, add your yeast/sugar and ferment away!

fermenter gets my vote as well....

15 gallon boil kettle! Make 10 gallon batches! You can use the 10 gallon kettle as a HLT.
More beer, same work!