Let’s Talk PSY (Predicted Spirit Yield)

Last month we introduced our new Non-GN Odyssey Whiskey Malt, which is crafted using a tailored process that results in a high Predicted Spirit Yield (PSY). This month, we’d like to take a few minutes to talk specifics of PSY.

Some of you may know that PSY is a measurement of the liters of pure alcohol produced from a tonne of grain. In this case, Odyssey produces 412 liters (108.8 gallons) of pure alcohol for every metric tonne (2204 lbs) of grain used. 

The unit of measurement for the alcohol produced is LAA (Liters Absolute Alcohol/MT (metric tonne) or L/MT, and simply means liters of 100% (200 proof) alcohol per metric tonne of grain used. Results are reported using metric values because testing for PSY was developed and most commonly reported in countries using the metric system.

PSY is measured in a lab using a procedure to assess the maximum potential yield of alcohol possible from the grain on a single sample, but it is unlikely that every distiller will be capable of achieving this value. Values may change if additional exogenous enzymes are used, processes are altered, or if other specialty malts are used.

The real value of this number is for comparing similar products used for making 100% malt spirits. The actual total potential alcohol production in a distillery will depend on additional factors (i.e., brewing, fermentation, & distillation efficiency). If you know the PSY of all the products in your recipe, you can more accurately assess your distillery’s efficiency.

Generally speaking (but there can be exceptions):

  • Higher protein = lower PSY
  • Higher extract = higher PSY
  • Higher fermentability = higher PSY
  • Higher enzyme content = higher PSY

Most brewing and distilling systems are not capable of achieving the maximum efficiency determined in a laboratory setting. In general, a distiller using a product or variety with a higher PSY should produce more alcohol.

For more information on our Odyssey Whiskey Malt, please contact your Briess representative, read last month’s blog: Introducing Non-GN Odyssey Whiskey Malt! or visit brewingwithbriess.com/Distilling/products_malt_pale

About Jordon Geurts

Jordon GeurtsPrior to Briess, Jordon worked with the USDA in its Cereal Crops Research Unit as a Lab Technician in the Barley Malt Quality Lab in Madison, WI. In his role at the USDA he specialized in small batch and pilot malting. In his current role at Briess, he provides technical support services for quality assurance, quality control, and R&D projects.

Posted in Distilling | Tagged , .
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