Just got 5gal of my Robust Porter put to bed. A recipe that I'm well pleased with that I wanted to go back to. My version is inspired in part by Anchor Porter; terminal gravity a bit on the high side, firm chocolatey malt flavors, moderate bitterness, and moderately strong hop aroma & flavor. I think the commercial version uses the same yeast that they use for the Liberty Ale; top fermenting, clean tasting, and to my palate very lightly mineraly. I go in a different direction, I like to use the Wyeast California Lager strain; yes, the supposed Anchor Steam yeast. With a not quite 1.080 OG terminal gravity should finish off in the low 20's, leaving a fair amount of sweetness that compliments distinctive and complex chocolatey malt flavors. As I'm thinking of it, maybe Nutella would be a good comparison. Another aspect of the Cali Lager yeast that I enjoy, is that bit of sulfur that this yeast strain produces. Adds a pleasantly appetizing touch in the finished beer. Bittered with Columbus & Magnum, finished with Amarillo & Cascade for firm bitterness and a lightly citrus-like hop character. Nice balance of flavors along with the chocolatey malt. Hmm, Robopo!