How do you come up with a recipe to use for "Second Runnings"?

Question

I recently brewed a Stone Russian Imperial Stout clone, per their official recipe in Brew Magazine. After collecting my wort, I was draining my mash tun and was saddened to see what appeared to be a perfectly drinkable stout in the making going down my alley.

When you make a really high gravity beer, specifically by increasing your mash not just increasing your boil, and you choose to make a lower gravity beer from the same grain, how do you come up with a recipe? Do you usually aim for a similar taste, with the same types of hops and yeast?

Answer 1

What you are wanting to do is basically a parti-gyle. This is where you run off multiple beers from a single mash. There are many different ways to go about this but the most common is to run off your strong beer and then your secondary. You can also blend the two worts to reach differing target gravities or do a 1/3-2/3 runoff. Here is an article written by Randy Mosher titled "Parti-Gyle Brewing" that outlines the processes and calculations necessary to estimate the gravities.

Answer 2

I just take a look at what I've got in my inventory and wing it. I almost always cap the mash with some additional grain, usually crystal of some sort. I've found that second runnings beers can have a thin body and adding more crystal helps with that. In addition, you don't have to worry about conversion using crystal or other non diastatic malts. As to deciding on the style, it depends on the base beer. If you start with something like an RIS your options are more limited than with something like a BW. With the RIS, you could make a dry stout or maybe even a brown ale. If you start with a lighter, more "neutral" beer first, you have more options of what to add to get to an entirely different style.