saccharification: one construct, many systems

During mashing the brewer holds crushed malt in warm water so the grain's own amylases (α- and β-amylase) hydrolyse gelatinised starch into fermentable sugars, chiefly maltose, alongside unfermentable dextrins; this conversion step is called saccharification and it sets how much sugar the yeast will later have to work with. Briggs's Malts and malting and Kunze's Technology brewing and malting describe the temperature rests that favour each enzyme and the iodine test that marks when conversion is complete. The referent is the enzymatic breakdown of a grain's starch store into sugars inside the mash tun, the same hydrolysis that reappears in biofuel plants and glucose-syrup refineries.[1][2]

Unit

The proportion of grain starch converted to fermentable sugar

Recovery means

Not applicable

Measured by

Tracked by the iodine (starch) test, extract yield, and the fermentability of the wort

In biofuel production the same construct is the central bottleneck: cellulase and hemicellulase enzymes hydrolyse the cellulose and hemicellulose of pretreated plant biomass into fermentable sugars that microbes then convert to ethanol. Lynd and colleagues' Microbial cellulose utilization and Himmel and colleagues' Biomass recalcitrance show why woody biomass resists this conversion and how enzymes and pretreatment overcome it. It is the identical polysaccharide-to-sugar hydrolysis as in a brewer's mash, scaled to lignocellulose and measured by sugar release rather than extract.[3][4]

Unit

The sugar yield released per mass of biomass

Recovery means

Not applicable

Measured by

Quantified by glucose and xylose release, enzymatic digestibility, and conversion yield after pretreatment

Food and fermentation industries run the same conversion continuously: after liquefaction, glucoamylase and related enzymes saccharify starch slurries into glucose and maltose syrups used as sweeteners and fermentation feedstocks. van der Maarel and colleagues' review of starch-converting enzymes of the α-amylase family sets out the enzymes and process conditions. It is the same enzymatic depolymerisation of starch to sugars as in the brewer's mash, operated as an industrial unit step and judged by the sweetness of the product.[5]

Unit

The dextrose equivalent of the resulting syrup

Recovery means

Not applicable

Measured by

Assessed by dextrose equivalent, glucose yield, and residual oligosaccharides