Crushing vs Grinding

[trevorgfisher_gmail.com (tgfish)]

@denny

@denny

I have my JSP set to 0.025" and run it with a drill.  I don’t squeeze the trigger very hard, and I’ll bet I’m at or under 150 RPM.  The husks stay very much intact, and I have never had a runoff problem, getting brewhouse efficiency around 95% (varies slightly with size of grain bill and hence proportion of sparge.)  I’d say slow speed is the key factor in good lautering, but as Denny points out,  pH is what matters for tannin extraction.

Yep.  My JSP is set as tight as it will go and run with a cordless drill at top speed.

Well next time I’ll have to just let 'er rip and see if it makes a difference.  I’m all for not hanging on to my drill any longer than necessary.

I think it will depend a lot on your lautering system.  With the braid I use, I’ve never had a stuck runoff.  And because I watch my pH, I’ve never had an astringent brew.

This. The crush size is not the be all end all, it can’t be considered in a vacuum. You have to consider your mash and lauter process & system. Are you full volume mash or are you lautering? Are you BIAB or false bottom or braid? Are you recirculating? Are you batching sparging or not at all? Etc etc.

I use a Grainfather system which means a false bottom (with larger gaps than I’d like), recirculation, and some kind of batch sparge’ish thing. For me, that has meant 0.037"+ crush size to get good flow during recirculation and avoid a stuck sparge. My overall brewhouse efficiency has suffered a bit with this large crush gap as I average 63-67% brewhouse efficiency but it’s much preferable to a stuck sparge mess or poor mash conversion from a restricted recirculation flow.

I’ve crushed finer when I’m trying to brew an especially big beer but then I supplement with rice hulls. Hell, I add rice hulls quite often just as insurance.