Newest Threads

**uberg33k** · 12-20-2012, 04:30 PM

Does anyone know the average particle size for pelletized hops? Better yet, a distribution curve for particle size? The only literature I can find regarding the pelletization process just generally describes hops being tossed into a hammer mill, reduced down to dust, then extruded into pellets. I can't find anything that defines what size the dust would be.

Thanks!

Misplaced_Canuck · 12-20-2012, 05:55 PM

I don't think you'll find a size distribution chart, as I'd venture to say that the hammering generates sizes all over the chart.

Have you looked at this here: http://www.hopunion.com/1017_HopPellets.cfm?p4=open

MC

**uberg33k** · 12-20-2012, 06:12 PM

Quote:

Originally Posted by Misplaced_Canuck

I don't think you'll find a size distribution chart, as I'd venture to say that the hammering generates sizes all over the chart.

Have you looked at this here: http://www.hopunion.com/1017_HopPellets.cfm?p4=open

MC

Well, that is somewhat more detailed than other resources I've seen, but still doesn't really answer my question. Thanks for the link though, it's a good read.

**HeadyKilowatt** · 12-20-2012, 06:26 PM

Are you trying to apply Stokes' Law to dry hops settling out in a fermenter or something?

'Cause that would be awesome.

Kaiser · 12-20-2012, 06:36 PM

there was some info in P. Wolfe's Dry hop paper: http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/34093/Wolfe_thesis.pdf?sequence=1

bdh · 12-20-2012, 07:00 PM

I know the Weibull distribution is popular for modeling particle size, but Weibull distributions are pretty flexible depending on the parameters used, so without some actual data points to fit it probably won't tell you much.

edit: I'm curious what you want to know the distribution for.

**sweetcell** · 12-20-2012, 07:02 PM

this might be of some use to you: this thread discusses the use of fine-mesh hop filters. a 300 micron filter seems to retain all the hop gunk (i can say this based on my own experience with one), while the 400 micron seems to be letting some stuff through although that hasn't been proven yet. tests will be carried out soon to compare the hop filtration properties of both sizes.

**uberg33k** · 12-20-2012, 07:19 PM

Quote:

Originally Posted by sweetcell

this might be of some use to you: this thread discusses the use of fine-mesh hop filters. a 300 micron filter seems to retain all the hop gunk (i can say this based on my own experience with one), while the 400 micron seems to be letting some stuff through although that hasn't been proven yet. tests will be carried out soon to compare the hop filtration properties of both sizes.

Lol, this is exactly why I wanted to know. That thread is a mess. So much confusion and contrary information there. I figured if you knew the particle size you're trying to filter and the viscosity of the media (wort), you could calculate the porousness of the filtering media and the media area needed for effective separation. That would more accurately account for what size filter mesh you should build with and how big a filter you need for a given amount of hops rather than some haphazard "we tried this and it worked/didn't" methodology.

**sweetcell** · 12-20-2012, 07:28 PM

Quote:

Originally Posted by uberg33k

That would more accurately account for what size filter mesh you should build with and how big a filter you need for a given amount of hops rather than some haphazard "we tried this and it worked/didn't" methodology.

i have no problem with the "this did/didn't work" approach in this situation. the overhead associated with fine-tuning filter size isn't worth it to me. it's not like you're gaining a new level of control over the finished product. "for this blind taste test, identify which beer was made with a 300 micron filter and which one is made with the 400"...

300 micron retains all, or practically all, of my hop gunk. great. off to brew

(and the viscosity of wort is variable depending on thickness/gravity of the beer being made, and it will further change during the boil so not sure what value you would use in your calculations)

**uberg33k** · 12-20-2012, 07:52 PM

Quote:

Originally Posted by sweetcell

(and the viscosity of wort is variable depending on thickness/gravity of the beer being made, and it will further change during the boil so not sure what value you would use in your calculations)

I realize this. However, since calculating the viscosity of wort is fairly trivial, you could make up a table that would tell you "effectively filters ___ oz of hops at ____ OG before clogging" for given filter size using a modified Darcy's equation. Then you just pick the filter that best meets your typical brew style and off you go ordering whatever model you need from Chad. It might even warrant buying several filters for various styles / hop bills or tell you "given your hop bill and kettle size, you aren't going to buy a filter big enough to work, so don't bother".