Grind - How coarse

[DSW]

Aside from practical considerations (i.e., processing spent stillage), is there any reason why you wouldn't grind to flour (or get grain in flour form?)? In my experience, no amount of exploding, cracking, etc of a coarse grind can you get you a flour yield. Most importantly: Does the pulverizing necessary to create flour affect taste? Put another way: Does a coarse grind yield a better tasting product? Thanks in advance.

[mattabv]

YIELD! TASTE DOESN'T CHANGE. CONVERSION>>>>>>>>>>>>>>>>>

[captnKB]

corn, barley, wheat, rye?? what kind of grain? ferment distill on grain or lauter? need more info to provide an answer

[esten88]

From what I have herd, there is a point where it is too fine and becomes a fire hazard.

[John McKee]

My two cents,

We have our grain milled into a flour offsite and delivered in 2000lb supersacks. Corn, Barley, Rye, Wheat.....doesn't matter. There are two primary reasons:

1. Safety = Milling is the most dangerous thing that can be done in a distillery. More than handling high proof, distillation, anything. Having this performed offsite at milling operations that are properly trained and have the proper equipment is just a smart idea.
2. Costs (CAPEX) = The electrical safety requirements for the mill room are high and as a result this means more expensive fixtures. An EXIT sign that is rated for the mill room will cost you $7000+. Balance that across the other electrical requirements and the CAPEX cost gets pretty high.
3. Costs (OPEX) = Look around for milling services and you'll find at least a 2-3 year balance in ROI of having someone else mill the grain for you vs. spending the correct CAPEX to install the proper milling system.
4. Costs (Insurance) = No milling onsite means that your insurance should be drastically lowered.
5. Yield = This is pretty straightforward. If you mechanically crack the grain to a flour, you have more access to starches available for conversion and as a result the potential for higher yield.
6. Grain on vs Grain off distillation = This is a unicorn pooping rainbows discussion. There is no difference in yield. Anyone suggesting otherwise has a poor understanding of distillation chemistry as it relates to beverage alcohol. However, there is a difference in system performance and uptime (which becomes greater) if you perform a grain-off distillation. Final caveat, we grain-on distill because with our system it just doesn't matter.
7. Still types = There is no difference here either, with the notable exception that properly designed continuous systems will recover 90%+ of all available alcohol during a single pass. In other words, there is no alcohol remaining in the "tails", which are referred to as bottoms in continuous stills.

Overall, the question of yield in milling types, flour vs cracked grain, was answered pretty soundly by Justin Aden at ADI 2012 (or maybe 2011). They did a lot of yield testing at MSU in the Artisan Spirits program and provided data that showed at 7-9% increase yield for flour milled washes vs cracked.

Cheers,

McKee

[DSW]

Thanks John. Great analysis. Final Question: Given that you use flour I'm assuming you have found no discernible difference in flavor?

Have you encountered any issues with mold?

We are also going the super sack route, and I want to make sure there is nothing I'm missing.

[John McKee]

DSW,

We have everything brought in via Super sacks, with bottom dumping sleeves (udder). No issues with Mold, the grain is double bagged inside the super sack in a plastic bag, so pretty airtight. No difference in flavor, just more booze per unit grain.

Cheers,

McKee

[miller]

John McKee hit it pretty much on the head. I think in general it doesn't make sense for most craft distillers to be in the milling business. A mill like ours can provide a grind much more uniform than they could reasonably afford to do themselves. Setting up a mill with the grain storage, cleaning equipment, grinding equipment, finish roduct storage and handling along with lab equipment is a just not needed when you can buy about any type of grain and grind you could want almost anywhere in the country.

[Skaalvenn]

Agreed. My farmer has our grain milled/bagged at a price so cheap that I'll probably never buy my own mill, even if we grow 50x in size. I think I pay $17 per ton. Even if I got a mill and equipped room for free, my time is worth far more.

[Michaelangelo]

McKee, cruising this while I watch the Bears implode against the Lions....Just curious as to what you are doing with your spent grains at the volume you produce. We chose to go the grist route as that was preferential to the farmer who picks up our spent grains to feed his pigs. When we were using flour our spent product had the consistency of mortar and we couldn't get anyone to take it. We gave in on the yield to make the disposal issue go away.

Your thoughts?

[John McKee]

Michaelangelo,

The fermented wash, grain and all, is run through the stills and discharged as a liquid slurry directly to the sewer. Basically, because we're running a continuous system, the stillage output is less than 2 gpm, which doesn't faze the treatment plant like dumping hundreds of gallons simultaneously from a pot still.

So...down the drain and gone.

We also recommend to the clients that purchase our systems (if they can't discharge to sewer like we can) of investing in a Russell Finex LSS or a Kason Centri-sifter to separate the solids from their mash, either pre or post distillation.

Cheers,

McKee