Using final runnings for a "mini-mash"

[simchuck]

I have done a couple of all-grain batches recently in which I took the final runnings to make a separate beer. In each case, I collected about 5 quarts of wort at a gravity of 1.012-1.014, then boiled this with about 1/2 lb of DME to make a nice session beer.

The only problem is that I am not really sure what I am going to end up with, since none of the recipe calculators will calculate gravity or color based on a given wort (gravity, volume, and color?) in addition to other fermentables (DME in my case). I can make a reasonable estimate of the gravity by manual calculation, and I just guess at the color.

Additionally, I haven't found anything discussing how the "balance" of the wort might be different in the final runnings compared to the initial runnings. For instance, do the early runnings include a higher or lower proportion of sugars, or dextrines, or proteins, or...?

Has anybody done this enough to be able to share some experiences with the results, and possibly have developed any guidance?

[Ozwald]

The early runnings are going to be mostly the easily soluable sugars. As you push it farther and farther, you're going to be getting stuff extracted out of the husk material mixed in there... stuff that isn't as easily soluable. As long as you're not pushing it too far, you're fine, but squeezing every last drop of sugar out of the mash comes with tannins, astringency, etc.

[dmtaylor]

All of the good malt flavors and colors come out with the first runnings. Mostly all you get at the tail end are residual sugars and a little color, with very low flavor. You also have a chance for tannins, although if you are batch sparging this is not a big concern like it would be for fly sparging.

I've made good beer with late runnings before, but not until I added a couple more pounds of malt and did a mini-mash like you've proposed. Otherwise the beer tasted extremely bland and watery. Extract could also do this for you, but doesn't taste the same as a mini-mash. As for figuring out the gravity and volumes, etc..... that would require a good bit of mathematics and experience. It's a bit of a swag until you get more experience.

[simchuck]

Temperature stays at or below my sparge temp, and I am pulling runnings with a gravity of at least 1.012. I don't check pH, but I also don't get any astringent character in the finished beer.

My question is really whether these final runnings will have different fermentability and proportion of proteins than the earlier runnings. Knowing that, I could make appropriate adjustments to compensate.

[Ozwald]

It depends

on the mash itself. Provided you're staying in the 'safe-zone', the later runnings should be pretty close to the same as the earlier runnings, in terms of fermentability & protein content. Your system may have an effect on it as well - no 2 mashtuns are going to work the exact same. You could always do some forced ferment tests to see what you're getting out of it.

[dmtaylor]

My question is really whether these final runnings will have different fermentability and proportion of proteins than the earlier runnings. Knowing that, I could make appropriate adjustments to compensate.

Sorry... that I really don't know. If I had to theorize, I would say that the latest runnings would have no beta amylase left so will be less fermentable, and will be closer to crystal clear than the early runnings and thus may have less protein. But these are just quasi-educated wild guesses.