AU2019100446A4 - The reprocessing of spent distiller's malted grain, using mold mycelium enzymes to convert residual spent grain material from brew mashing to sugars suitable for further fermenting and subsequent distilling. - Google Patents

Abstract

Abstract The invention provides for a distillery waste grain reuse method. Waste malted barley grain is subjected to mold mycelium which completely permeates the waste grain. The mold mycellium Botrytis cinera can be used to enhance/alter the flavour profile of whiskey.

Description

Distillery Malted Grain Waste Re-Use Option.

As a self-introduction, I'm a semi-retired distiller of beverages. I set up a Hobart distillery, then solely built maturation stocks of whisky for 3 years. My grain vodka, a whisky liqueur I named Mellifera and my 2 years old whisky have now won several International gold medal awards in tasting events.

Approximately 3 months ago, I obtained a bulk bag (Approx 300 KG) of spent fresh malted barley from the distillery, with the intention of composting it for my vegetable garden. After the opened bag sat in my paddock for slightly over a week, I noticed that Tasmanian honey bees were feeding on the surface of the moist spent barley. Scores of bees were constantly present for several weeks during daylight hours. Once the bee numbers had diminished, I inspected the now dry spent grain sub-surface and found masses of grey mold mycelium, which I assume was Botrytis cinera.

Knowing that the distillery's mash sparging would have exhausted soluble starch and maltose, I assumed that B.cinera mycelium enzymes had converted the grains residual pectin and cellulose to sugar. I presumed that these sugars were malt di-saccharides and possibly tri-saccharides, because European wasps which were prolific in my region at this time were not interested in the malt sugars. I'm aware these wasps prefer monosaccharides such as fructose and sucrose.

Knowing the principles of "Noble Rot" in wine grapes and how Botrytis cinera increases wine sweetness and develops a unique flavour, I considered that this mold could possibly do the same to waste malted barley to produce at a maximum a more intensely flavoured whisky, or at a minimum create additional neutral flavoured spirit from waste grain. I intend to evaluate this idea.

If proven to be commercially viable and food safe, it would allow distilleries to make additional product from their waste grain and possibly that from breweries.

Claims (1)

1. Distillery Waste Grain Reuse Method. • Spread freshly extracted malted grain in stackable trays approximately 20mm deep. • Place in a temperature (20-25 C) controlled cabinet with ventilation for a yet to be determined period, until mold mycelium completely permeate the waste grain. • Assess saccharide conversion by soluble extraction. • When saccharide content peaks, use a 3:1 water to solid and heat sterilise the mold affected grain. Check if soluble starch is also in the liquid. If so, quickly cool to 65C, then either add amylase enzyme or preferably freshly malt grain liquid from the usual mashing in brewing method. Subject to the amount of starch not converted by mold enzymes, this malted barley liquid amylase addition could be added at 10-20% of the mold liquid extracted, to further convert remaining soluble starch to saccharide usually within an hour at 60-65C.. • Repeat sparge and coarse filter off the liquid in a standard mash tun, then quickly cool to assist pasteurisation of the liquid. This liquid to then be pumped through a centrifuge decanter to further isolate residual fine solids and mold debris. • Assess the liquid's specific gravity with a hydrometer and correct the result to 20C • Add hydrated brewing yeast to the filtered liquid and ferment in the usual manner. • On completion of the fermentation reaction, reassess the specific gravity with a hydrometer and alcoholmeter. • Allow fermentation sediment to settle, preferably in a conical vessel and decant off from above the sediment. Put the decanted liquid through a 5 micron bag filter and reflux distil the wash in the usual manner. I prefer 2-3 reflux distillation pass cycles and separate fore-shots, heads, hearts and tails in the usual manner. • Then test that the distillate is food safe. Ethyl carbamate levels may have increased from the mold enzyme reaction with the grain tissue. • If the results and quantity is favourable, consider repeating the process with a fresh batch of wash in a pot still, which unlike the reflux still will retain grain/fermentation flavour. Possibly this will produce an enhanced whisky flavour, similar to that produced by Botrytis cinera's creation of "noble rot" in wine grapes. This produces the premium priced sweet dessert wine called Essencia.