Proposed: A Sorghum Malt Evaluation Standard (GFB-SME, draft v0.3)
Status: proposed, draft v0.3, never ratified by anyone. This is a discussion document in the same spirit as The Maltose Mash: a specific, criticizable design beats an empty field. If you run a lab, a malting program, or a breeding program and this draft is wrong for your work, we want to know exactly where.
What this proposal answers
The full case file lives in the Evaluation Methods survey — every methodology the field has used, each reviewed on its own page. The one-paragraph version: the only real standard, SABS/SANS 235, serves South Africa's opaque-beer industry where the malt is the conversion engine, and it became everyone else's stopgap because it was the only sorghum-shaped standard on the shelf. Everything else was borrowed — barley methods that measure sorghum's deficits, institute methods that fragmented the units, research conventions built for different questions, and commercial panels built for other grains entirely.
Our proposal is for the product class none of the borrowed tools were built for: clear, stable, packaged gluten-free beer brewed with external enzymes, where the malt's job is character.
The core problem in the borrowed methods
Outside the opaque-beer world, sorghum malt evaluation was barley evaluation with the labels changed. The reference methods — congress mash, ASBC/EBC malt analysis — were built for a grain whose malt converts itself. Run them on sorghum and the numbers mostly measure sorghum's enzyme deficit: low DP, low alpha, incomplete conversion, and an extract figure gated by the enzymes rather than the malt's actual contribution. Decades of screening data (including ours) scored cultivars DP-first because that's what the borrowed methods measure best.
Our position, built at commercial scale: that's measuring the wrong thing. In a working gluten-free process, external enzymes own conversion. The malt's job is flavor, color, body, clean wort, and yeast nutrition. An evaluation standard should measure the job, not the handicap — and as an aside we'll defend anywhere: further research into maximizing native sorghum enzymes is effort the brewing side of the field doesn't need.
Principle 1 — Evaluate in an external-enzyme reference mash
Replace the congress mash with a standardized enzyme-added mini-mash: fixed heat-stable alpha-amylase and saccharification doses (specified per gram of grist, products and activities stated), a fixed temperature program modeled on the 190°F liquefaction baseline, fixed water ratio in L/kg. Conversion is held constant by design — so every difference between samples is the malt, not the enzymes.
From that one mash, the measures that matter:
| Measure | Why it's first-class |
|---|---|
| Extract (% d.b., method stated) | The malt's material contribution, ungated by native enzymes |
| Wort turbidity + clarity | The practical problem that decides whether sorghum beer is drinkable — method and units specified below (v0.3), as the 2002–2004 program measured but did not specify |
| FAN (ppm) | Sorghum's real deficit; drives yeast performance downstream |
| Wort color | Character contribution, kiln response |
| Wort pH and viscosity | Process-fit signals |
| Defined sensory panel | Malt is for taste — wort and hot-steep aroma/flavor scored against a published lexicon, not "seemed fine" |
Native enzyme measures (DP, alpha-amylase) become optional descriptive data — reported if measured, never a ranking criterion, and always with the unit system named.
The reference mash, specified
Added in v0.2 so a laboratory can actually run this — doses derived from our documented production practice, offered for criticism, not validated as a lab method:
GFB-SME Reference Mash
- Protocol
- GFB-SME
- Version
- Draft v0.2
- Effective
- August 2026
The proposed standard's enzyme-added mini-mash: conversion held constant by design, so every difference between malt samples is the malt, not the enzymes. Doses are GFB's documented production doses scaled per kilogram of grist — a starting point offered for criticism, not a validated laboratory method.
Draft status: Proposed, draft v0.2, never ratified by anyone. Product names churn — the binding specification is the enzyme class plus the declared activity on the label, and every report must state the exact product, declared activity, lot, and dose. If your laboratory substitutes equivalent-activity products, say so: that friction report is exactly what this draft needs.
Declare before the first sample
Enzyme into the full-volume water
- Do
- Add heat-stable bacterial alpha-amylase at 4.4 mL/kg of grist (Termamyl SC DS class) to the full-volume water.
- Add
- Heat-stable alpha-amylase, 4.4 mL/kg (state product, activity, lot)
- Advance when
- Dosed and mixing.
- Record
- Product, declared activity, lot, dose
Grist in gradually, hot
- Do
- With the water at 88°C, add the grist gradually with continuous stirring.
- Add
- Grist, gradually
- Advance when
- Grist fully in, mash even.
- Record
- Grist mass (d.b.) · Actual mash-in temperature
The 60-minute hold
- Do
- Hold 88°C for 60 minutes with continuous stirring.
- Add
- None
- Advance when
- Hold complete.
- Record
- Temperature log · Viscosity observations
Glucoamylase to a fixed endpoint
- Do
- Cool to 63°C. Add glucoamylase at 1.65 mL/kg (Amylase AG 300L class). Hold 45 minutes.
- Add
- Glucoamylase, 1.65 mL/kg (state product, activity, lot)
- Advance when
- Hold complete.
- Record
- Product, activity, lot, dose · Cooling time
End enzyme work
- Do
- Raise to 82°C and hold 10 minutes.
- Add
- None
- Advance when
- Hold complete.
- Record
- Time to temperature
The measures that matter
- Do
- Filter. Measure extract (% d.b., method stated), FAN (ppm), turbidity, wort clarity, wort color, pH, and viscosity. Run the sensory panel per Principle 4.
- Add
- None
- Advance when
- All declared measures recorded with units.
- Record
- Every measure with its method and units · Sensory scores against the published lexicon
| Step | Action | Target | Add | Advance when |
|---|---|---|---|---|
| 1. Dose: more detail | Add heat-stable bacterial alpha-amylase at 4.4 mL/kg of grist (Termamyl SC DS class) to the full-volume water. | Full water volume — |
| Dosed and mixing. |
| 2. Mash in: more detail | With the water at 88°C, add the grist gradually with continuous stirring. | 88°C (190°F) at 3.0 L/kg — |
| Grist fully in, mash even. |
| 3. Liquefy: more detail | Hold 88°C for 60 minutes with continuous stirring. | 88°C 60 min | None | Hold complete. |
| 4. Convert: more detail | Cool to 63°C. Add glucoamylase at 1.65 mL/kg (Amylase AG 300L class). Hold 45 minutes. | 63°C (145°F) 45 min |
| Hold complete. |
| 5. Mash out: more detail | Raise to 82°C and hold 10 minutes. | 82°C (180°F) 10 min | None | Hold complete. |
| 6. Measure: more detail | Filter. Measure extract (% d.b., method stated), FAN (ppm), turbidity, wort clarity, wort color, pH, and viscosity. Run the sensory panel per Principle 4. | Filtered wort — | None | All declared measures recorded with units. |
Run each step with its checks and context
Use the run sheet during a routine mash. Use these expanded steps when setting up the process, training an operator, documenting a deviation, or diagnosing unexpected behavior.
Enzyme into the full-volume water
Objective
Active liquefaction enzyme before grist — the same rule the production process lives by.
Operating instruction
Add heat-stable bacterial alpha-amylase at 4.4 mL/kg of grist (Termamyl SC DS class) to the full-volume water.
- Heat-stable alpha-amylase, 4.4 mL/kg (state product, activity, lot)
What good looks like
Dosed and mixing.
Watch for
No additional step-specific warning.
Record
Product, declared activity, lot, dose
Grist in gradually, hot
Objective
Even wetting at liquefaction temperature without clumping.
Operating instruction
With the water at 88°C, add the grist gradually with continuous stirring.
- Grist, gradually
What good looks like
Grist fully in, mash even.
Watch for
No additional step-specific warning.
Record
Grist mass (d.b.) · Actual mash-in temperature
The 60-minute hold
Objective
Full liquefaction on the documented production baseline — the fixed half of holding conversion constant.
Operating instruction
Hold 88°C for 60 minutes with continuous stirring.
What good looks like
Hold complete.
Watch for
No additional step-specific warning.
Record
Temperature log · Viscosity observations
Glucoamylase to a fixed endpoint
Objective
Drive conversion to a fixed, maximal endpoint so extract measures the malt, not the conversion chemistry.
Operating instruction
Cool to 63°C. Add glucoamylase at 1.65 mL/kg (Amylase AG 300L class). Hold 45 minutes.
- Glucoamylase, 1.65 mL/kg (state product, activity, lot)
What good looks like
Hold complete.
Watch for
No additional step-specific warning.
Record
Product, activity, lot, dose · Cooling time
End enzyme work
Objective
A clean stop before filtration.
Operating instruction
Raise to 82°C and hold 10 minutes.
What good looks like
Hold complete.
Watch for
No additional step-specific warning.
Record
Time to temperature
The measures that matter
Objective
The standard ranks for the beer, not the assay: clean wort and real extract gate; flavor differentiates; FAN sets the nutrition plan.
Operating instruction
Filter. Measure extract (% d.b., method stated), FAN (ppm), turbidity, wort clarity, wort color, pH, and viscosity. Run the sensory panel per Principle 4.
What good looks like
All declared measures recorded with units.
Watch for
Reporting DP or alpha-amylase as a ranking criterion — they are optional descriptive data here, never rank.
Record
Every measure with its method and units · Sensory scores against the published lexicon
Design notes, criticize freely: glucoamylase fills the saccharification slot because it drives conversion to a fixed, maximal endpoint — extract is then ungated by conversion chemistry and every difference between samples is the malt. The 3.0 L/kg ratio sits at the thin end of the documented production band (2.2–3.0 L/kg) for laboratory handling. Products churn names — our own records track the same enzyme under multiple labels — so the binding specification is the class plus the declared activity on the label, and every report must state the exact product, declared activity, lot, and dose per Principle 3. If your laboratory substitutes equivalent-activity products, say so; that report is exactly the friction data this draft needs.
Turbidity, specified
A standard that promotes turbidity to a first-class measure and then leaves it methodless would be failing its own Principle 3. So, added in v0.3:
Turbidity. Reported in formazin units (FTU/EBC formazin; NTU acceptable where the instrument reports it), with the unit and instrument type declared — nephelometric or absorptiometric, calibrated against a formazin standard. Two values per wort sample: as-run (wort as the reference mash produced it, settled 10 minutes, no centrifuge) and clarified (after a declared spin or filtration step). The pair is the measure: as-run tells the brewer what the lauter and kettle will see; the difference tells them how much of the haze is removable solids versus stable colloid. A single undeclared number is non-conforming.
The two-value form encodes documented production practice — our own 2014–2017 QA log recorded turbidity in FTU at two spin levels, batch by batch. The 10-minute settle is a proposed convention, exactly the kind of detail an adopting lab should pressure-test.
Principle 2 — The reference malting schedule
Screening comparisons need a shared malting method. We propose the Madison bench schedule as the reference, because it's documented and we've published its output: 26-hour steep (8h wet / 1h air / 8h wet / 1h air / 8h wet) at 24°C; germination at 24°C with spray-watering to 41% moisture (wet basis); endpoint at 1:1 acrospire-to-grain length (~72 hours bench scale); five-stage kiln finishing at 85°C. The 85°C finish is deliberate doctrine — character over enzyme survival.
Principle 3 — Mandatory declarations
Every archived screwup in our own records traces to an unstated basis. So the standard makes these declarations mandatory on every report:
- Moisture basis — wet or dry, on every moisture and extract figure.
- Units on every enzymatic measure — °Lintner, °WK, ASBC, or SDU, never bare numbers. (Our own 2002–2004 dataset carries an unlabeled DP column; it's published with a warning because the units died with the worksheet. Don't be that worksheet.)
- Ratios in L/kg, with any local units in parentheses.
- Germination length and scale — bench and production timelines differ by days.
- Cultivar identity — named, or explicitly declared anonymous. Anonymous grain is a different, lesser class of result.
Principle 4 — Rank for the beer, not the assay
A scoring framework, not a single index: clean wort and real extract are gate criteria; flavor panel differentiates; FAN sets the nutrition plan; color maps the malt to styles. A cultivar with modest numbers and a clean, flavorful wort outranks a hazy DP champion — because the first one makes better beer with external enzymes, and the second one makes a mess with slightly less enzyme.
What would make this a real standard
Adoption, criticism, and iteration — in that order. Specifically: labs running the reference mash and reporting friction; breeding programs (the University of Nevada, Reno program is building exactly the methodology this draft addresses) comparing it against their own protocols; and anyone publishing sorghum malt data adopting the mandatory declarations even if they reject everything else. The declarations alone would fix half the field's comparability problem.
Version history
- v0.3 — 2026-08-23. Turbidity method and units specified (formazin units, declared instrument, as-run + clarified pair) — the standard's own units discipline applied to its headline measure. Approved by Craig from the drafting record.
- v0.2 — 2026-08-09. Reference mash specified with products-by-class, doses, temperature program, and ratio; "proven at commercial scale" softened to "built." Prompted by academic-readiness review: a standard nobody can execute from the page is a position paper.
- v0.1 — 2026-08-08. Initial draft.
Related
- Data Catalog — the datasets behind this proposal
- Why Native Malt Enzymes Are Not Enough
- The Maltose Mash — the same spirit, applied to mash design
- Contribute Research
Source and Validation Notes
This proposal synthesizes Bard's commercial malting and brewing experience, the USDA-ARS screening program's documented methods, and the site's published doctrine. It is a draft authored to be criticized; nothing here has been ratified by any standards body, and the reference-mash enzyme specification (products, doses, activities) is deliberately left at v0.1 as the first thing adopters should pressure-test with us.