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Hi folks,

My client is implementing the diacetyl method via spectrophotometry (Beer-25). Most of the supplies are already in house but for a few, I was wondering if those of you running it have any good (cheaper but adequate) substitutes for some of the supplies. For example: 
- lab grade 95% iso vs a ~grocery store~ brand 99% diluted with possibly deionized water?
- glass funnels vs plastic (I assume this may not be one to substitute based on corrosion potential)? 
- glass stoppers/caps for the volumetric flasks vs rubber/silicone stoppers
- lab grade creatine vs creatine powder supplement (if the supplement can be adjusted to the 98% spec if necessary)
- Ferm cap vs whichever anti-foam the method states (I have successfully used ferm cap in other distillations, with benchmarks met/tested)

Any others you can think of or any help here is greatly appreciated. Thanks and cheers!

Hello,

We run this method in our lab daily.  We have not tried using cheaper alternatives to lab grade chemicals, but I would proceed with caution there.  The materials are not very expensive compared to the labor required to run the method (and compared to a high VDK batch of beer), so I question whether it would be worth throwing off your results to spend labor on bad data.  That being said, your customer could spend some time trialing these things out and comparing against results from materials of recommended quality and make a decision from there for future purposes.  Making sure to run set of calibration standards frequently would be a good way to remove variability from the alternative materials, but I would still recommend first using the lab grade materials to compare against.  I bet they could even "borrow" a couple days of lab grade materials from a nearby lab to test against if there is one in the area already running the method... send them my way if they are anywhere near Seattle :) 

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Robert Fulwiler
Technical Director
Fremont Brewing Co
Seattle WA
(206) 484-2690
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