Ask The Brewmasters

We're working on building out a new facility and the current grain handling system augers-in malt at approximately 14# per minute.  With a 30-40bbl brewhouse capable of 2,800# mashes, this means batches will take around 3 hours to mill into our grist case.  While an auger upgrade is likely in the future, I'm trying to decide how to make the best use of our production team's time until then.  Being able to mash-in first thing in the AM is best, so my plan would be to have the closer pre-mill the following day's batch, which could result in up to an 18 hour gap between milling and mashing.  Is anyone aware of any techincal publications (or anecdotal evidence) regarding if an 18 - 24 hour window between milling and mashing will have any measurable impact on beer quality? Thanks in advance! 

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Jeremy Castellano
Director of Brewing Operations
Mission Brewing
San Diego, CA
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We always mill the next batch the night before.  Also, since we do not brew on weekends, we will mill Monday's brew on Friday night.  As long as the grist case remains dry, this policy works fine for us.  We have not seen any detrimental effects to the quality by doing this technique.  I too though would be interested in finding research on this topic.  I've known breweries that purchase pre-milled malt and always questioned this policy. 

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Chris Hotz
Quality Manager
Societe Brewing Co
San Diego CA
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The short answer is yes there are measurable things you can see when premilling, but keep in mind we can measure some pretty small things.

I've worked for breweries that this was a huge no from due to the effects that we would measure on flavor stability when approaching the end of our shelf life.  While they were measurable quantitatively we didn't see it sensorily stand out as much versus beers that were not milled in.  

Many brewers out there are making great beers that buy pre milled malt and as long as you don't have shelf life issues won't be perceived by the customer.

I would recommend staying away from light lagers or low hopped beers as you might see some earlier oxidation characteristics come up but I really suspect you won't.

It might not hurt to pre grind a batch in your current facility or if you have a small pilot just give it a test.  I would let your premilled go over the weekend and see.  I suspect your panel won't be able to tell a difference base upon personal experience.

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Timothy Hawn

Director of Operations
Craft Kettle Brewing Equipment
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