Best Grind Setting for GrainsSaturday, March 28th, 2009
It pays to listen to your grist, it can tell you a lot about your brew day before you ever mash in, if you look and listen to what it is telling you. Do not underestimate the importance of a good crush and the pitfalls of a bad crush on brew day. Your brewing efficiency can be negatively impacted if the grain is milled too coarsely, making your beer weaker. However, if you grind too fine you risk a stuck sparge – which really sucks! This article will tell you how to best mill your grain and provide photo examples.
(Fig. 1) The GOOD crush: A good crush is one that produces little flour, but fully separates the inner meal of the kernel from the husk. In doing so, the husk must be left mostly intact. The benefits of this crush are little flour which can cause a sticky stuck sparge, excellent mash conversion due to the fully exposed inner kernel, no astringency from shredded husks and a good filter bed from leaving the husks intact. Gap set to 0.035″.
(Fig. 2) The BAD crush (too coarse): A coarse crush can be found relatively easily when buying pre- milled malts from many suppliers. Many homebrew stores crush their grains more coarsely to provide less of a chance of a stuck sparge, but this will also cause you low mash efficiency resulting in the need to use more grain to achieve the target OG of your brew. This crush is defined by no flour, cracked but not separated inner meal of the kernel, and yes, some whole kernels left in the grist. You will see poor mash efficiency, no astringency from shredded husks and a great filter bed since you are dealing with such large kernel/husk portions. Gap set to 0.065″.
(Fig. 3) The BAD crush (too fine): When a poor crush is defined as too fine, it is generally caused by someone being a little over zealous in achieving high mash efficiency. A good goal, but you can go too far. This crush is defined by a lot of flour, shredded husks and nearly pulverized meal from the kernel. The results will be excellent mash efficiency (if you can actually drain the MLT), a poor filter bed from the shredded husks, some astringency from the shredded husks and an almost certain stuck sparge from the flour. For the record, labs will do a fine grind when analyzing grain extract potential but home brewers should avoid such a fine grind. Gap set at 0.025″.
Use the crush setting specified by figure 1 above and you will have a better brew day!