Many of todays highly modified malts reach full conversion in very short times, especially at the temps listed above (assuming proper dough in and mash PH). If you're mashing closer to 150F, or aren't confident in your mash PH, or are using home kilned malt, you'll need to mash longer. Many people (myself included) have shown conversion using the iodine test in as little as 15 min. The 10 min for the porter does sound pretty short, but who knows. The others look to me like enough time for complete conversion given proper mash PH. I still prefer to mash for 45-60 min just to be sure, and mashing longer really doesn't hurt anything.
Originally Posted by Groo
I think they are doing a two step mash for a total of 60 minutes.
For the pale ale it says to hold it at 156 for 20 minutes then add water until it comes up to 165. Then sparge with 168 water.
That's not a step mash, it's a single rest mash and then a mash out. 156F would be the last/highest rest if it were a step mash.
Originally Posted by lucasweb
My next question is what are the benefits of a two step mash?
Depends on the step temperature. Acid rests are done to generate acids to acidify the mash naturally for lighter beers. For wheat beers it can be used to create ferulic acid which reacts with bavarian yeasts to create the distictive phenols. Protein rests help break down proteins and aid in clarity. They are most common when mashing higher quantities of protein rich grains like wheat, rye, and oats.