Proposed: A Sorghum Malt Evaluation Standard (GFB-SME, draft v0.7)
Status: proposed, draft v0.7, 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.
How to read this
| If you are | Start at |
|---|---|
| Deciding which sorghum to malt | Selecting sorghum — what to measure, and what other regimes measure |
| Running the evaluation in a lab | The reference mash — a full run sheet, and the four principles that govern it |
| Judging whether a result is normal | What these measures actually read — published ranges |
| Wondering why we ignore diastatic power | Where diastatic power stands |
| Looking for the open work | What would make this a real standard |
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 standard with real adoption, 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 nearest 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.
Why every regime is shaped the way it is
A seven-region survey behind this revision found one variable predicting what each region measures: what converts the starch. Fix that, and the criteria follow.
| What converts the starch | Where | What that regime measures | What it ignores |
|---|---|---|---|
| The malt itself | South Africa opaque beer; Nigerian industrial malting; Indian malting | Diastatic power — under SABS 235 the malt is bought and sold on it. Germination vigour, extract | Clarity, foam, packaged stability |
| External enzymes | The process this standard serves | Extract, turbidity, FAN, colour, sensory | Diastatic power |
| A microbial starter | China, baijiu — qu saccharifies and ferments simultaneously | Starch type and amylopectin ratio, tannin as microbial substrate | DP, and malting itself — there is no malting step |
| Nothing — commodity grading | US FGIS; Grain Trade Australia | Test weight, damage, screenings, soundness | Every malting property |
None of these is wrong. Each is correct for its product.
What does exist, and why it does not cover this case
A fresh survey found more published standards work on sorghum than earlier drafts of this page credited. Recorded plainly, because a standard that overstates the emptiness around it is making the same error it warns about:
| Document | What it covers | Why it does not answer this question |
|---|---|---|
| SABS / SANS 235 (1970) | Diastatic power of sorghum and millet malts, in SDU | Built for opaque beer, where DP is the traded property. Asks nothing about clarity, flavour, foam or packaged stability |
| ISO 9648:19881 | Sorghum — determination of tannin content. Ferric ammonium citrate assay, spectrometric at 525 nm | A grain method, not a malt evaluation. But it is the method this standard's scope condition cites |
| EAS 757:2011 (East African Standard)2 | Sorghum grain specification, three grades — moisture max 13%, test weight min 71/62/62 kg/hl, tannin max 0.5% by ISO 9648, crude protein min 7.0%, total aflatoxin max 10 µg/kg, plus microbiological limits | A grain specification for human consumption, and the most malting-relevant of the grain standards we found. Carries no malt evaluation |
| US FGIS (7 CFR 810.1404)3 · Grain Trade Australia CSG-1/2 | Commodity grading — test weight, damage, screenings, soundness | No germination requirement, no malting parameter |
| Analytica EBC 3.6.1–3.6.3, 3.7 | Germinative energy and germinative percentage | Barley methods, applied to sorghum in screening work rather than written for it |
So the gap is narrower and more specific than "nothing exists". Sorghum has an ISO tannin method, a regional grain specification, and a national malt-DP standard. What we have found no published standard for is evaluating sorghum malt as a character ingredient in an external-enzyme process — the row this document occupies.
Two long-established commodity grain standards — FGIS and GTA — carry no malting parameter at all. They grade grain for trade, and malting is not what they are for.
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.
Where diastatic power stands
The most contested position in this document, stated in one place rather than assembled from fragments.
What this standard does with DP. Diastatic power and α-amylase are optional descriptive data — reported if measured, never a ranking criterion, always with the unit system and the method named.
Why. In an external-enzyme process, conversion is supplied by the mash, not the malt. Ranking cultivars on DP ranks them on a capability the process does not use, while the properties it does use — extract, clarity, flavour, yeast nutrition — go unmeasured.
This is not an eccentric position, but it is not the majority one either. Of the three conversion strategies the survey found, two make DP irrelevant to the malt — ours, and China's baijiu industry, where a microbial starter converts and sorghum is not malted at all. By volume of sorghum malt actually evaluated, the malt-converts regime still dominates. The point is narrower and stronger: DP-first evaluation follows from one conversion strategy. It is not a property of sorghum.
What the cost of the other axis looks like, measured. Two published screens applied DP-first criteria and set most of their material aside:
| Screen | Material | Criterion | Passed |
|---|---|---|---|
| Garzón & Drago (2018)4 | 24 white and red hybrids | ≥22 °DP/g d.b. and ≥60 UBetamyl/g d.b. | 8 of 24 |
| Komlaga et al. (2021)5 | 26 Ghanaian varieties | Suitable for lager malt without supplementary enzymes | 5 of 26 |
Both criteria are correct tests of whether sorghum malt can convert its own starch. Neither asks our question. Of the 37 cultivars those two screens set aside, an unknown number may produce clean, flavourful, well-extracted wort in an external-enzyme mash and be invisible to a DP-gated screen. That is the practical cost of evaluating on the wrong axis.
What we still publish, for those who need it. Our 25-cultivar screening reports DP 19.2–45.7 °ASBC at 3-day germination and 19.7–40.1 at 4-day, against a conventional barley context near 100–140 °ASBC. For anyone reporting in SDU, the unit SABS 235 established: one malting-optimisation study reports sorghum malt diastatic power across 20–60 SDU/g, with trial malts at 40.17 SDU/g and an optimised target of 42.2 SDU/g.6 That study malted for pito, a traditional West African beer in which the malt converts, so those figures belong to the other side of the conversion map.
And a warning about comparing any of them. Published work finds the IoB and EBC methods correlate closely with each other on sorghum DP (r ≈ 0.97)7 — so a laboratory choosing between those two is not the problem. That correlation says nothing about figures reported as °ASBC. One published comparison puts sorghum malt at 4.37 °ASBC8; our range above runs 19.2–45.7. That is close to an order of magnitude, and agreement between two other methods cannot explain it. The likeliest explanation is basis — what was measured, on what material, against what reference — though different malt is not ruled out. Two numbers can share a unit and still not be comparable. That is why Principle 3 requires the method as well as the unit, and why reconciling the enzyme figures is an open ask.
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. The full run sheet is below.
From that one mash, the measures that matter:
| Measure | Status | Why it's first-class |
|---|---|---|
| Extract (% d.b., method stated) | Required | The malt's material contribution, ungated by native enzymes |
| Wort turbidity + clarity | Required | The practical problem that decides whether sorghum beer is drinkable — method and units specified below |
| FAN (ppm) | Required | Sorghum's real deficit; drives yeast performance downstream |
| Wort color | Required | Character contribution, kiln response |
| Wort pH and viscosity | Required | Process-fit signals |
| Defined sensory panel | Required | Malt is for taste — wort and hot-steep aroma/flavor scored against a published lexicon, not "seemed fine". The lexicon this asks for is now drafted: GFB-SML, with the panel method on Sensory Evaluation of Gluten-Free Malt |
| Gelatinisation onset | Proposed, descriptive | Separates a poor malt from an incompletely gelatinised one — see below |
| Diastatic power, α-amylase | Optional, descriptive | Never a ranking criterion — see Where diastatic power stands |
What these measures actually read
A standard that says what to measure and never what the answer looks like leaves a laboratory unable to tell a normal result from a broken run. From our own 25-cultivar screening — one standardized malting schedule, two germination lengths:
| Measure | 3-day germination | 4-day germination | Barley, for context |
|---|---|---|---|
| Extract (% d.b.) | 31.6 – 67.8 | 30.6 – 66.1 | near 80 |
| FAN (ppm) | 66 – 119 | 59 – 140 | 140 – 200 |
| Diastatic power (°ASBC) | 19.2 – 45.7 | 19.7 – 40.1 | 100 – 140 |
| α-amylase (DU) | 48.0 – 86.2 | 59.7 – 119.9 | — |
Read these as what one screening reported, not as acceptance limits. They are the spread across 25 cultivars under one schedule, published so a candidate can be placed against something. The barley column is conventional published context, not measured in that dataset.
Colour, pH and viscosity — what we can and cannot supply. Our 2014–2017 production log carries 155 records of colour and pH through a working process: colour 3.60 – 25.10, median 8.80, and pH 3.40 – 6.01, median 3.82. Read those as process and packaged-product values, not reference-mash wort values — they describe what a production chain held, not what a cultivar screen produces. For wort viscosity we have no figure to publish in any unit, and none was found in the survey. It stays a required measure because it is a real process-fit signal, and it is the measure most in need of an adopting laboratory's first result.
One caution about FAN specifically. Sorghum FAN runs near half of barley's — compare the ranges above. What that FAN is made of matters as much as how much there is, and published work on sorghum malt's amino-acid composition disagrees, including on how much proline it carries. Until that is settled, read a ppm figure as a quantity, not as a statement about yeast nutrition.
Turbidity, specified
A standard that promotes turbidity to a first-class measure and then leaves it methodless would be failing its own Principle 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.
What the pair reads in production. Across 89 paired samples in that log:
| FTU 90 | FTU 25 | |
|---|---|---|
| Range | 25 – 6,899 | 1 – 3,736 |
| Median | 161 | 70 |
| Median at stage C — fermented, before dilution | 316.5 | 260.0 |
| Median at stage F — after dilution | 101.0 | 41.0 |
| Median at stage X — packaged | 91.5 | 33.0 |
The ratio between the two spins ran a median of 3.42, across a range of 0.74 to 55.0. That ratio is the measure this section argues for, and it is here so an adopting laboratory has something to compare against.
What those stages are, and one caution. The log's own shorthand does not define its stage letters, so the descriptions above are read from the gravity and alcohol recorded at each. Stage C is fully fermented beer — about 7.1% ABV at pH 3.76 — not wort; there are no paired turbidity readings from the wort stage at all. And between C and F the log records the high-gravity dilution, with original gravity falling from about 16.2 to 11.2 °P. So part of the fall from C to F is dilution, not clarification. None of these figures is a kettle-wort value, and a laboratory measuring wort should not compare against them.
One honest limit on this dataset. The log heads its column FTU 90, and what the "90" designated — spin time, speed, or measurement geometry — did not survive in the record. The numbers are real production values; the basis behind the pair is partly lost, which is precisely why this standard requires the declaration it does.
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.
Why these settings, and what they trade away
A reference schedule that does not show its tradeoffs is an assertion:
| Setting | Why this number | What the alternative is |
|---|---|---|
| Germination at 24 °C | It is the measured β-amylase optimum — highest activity across the 24–32 °C range investigated9 | Other published work germinates warmer; one hybrid screen malted at 30 °C for brewing and 25 °C for a bio-functional end use on the same grain4 |
| ~72 h germination | Endpoint is acrospire length, not the clock | α-amylase peaks at 96 h and is reduced significantly after 120 h.10 We stop short of that peak deliberately: under external-enzyme doctrine the malt is not supplying conversion |
| 41% germination moisture | Documented practice | One sorghum and pearl-millet study recorded steep-out moisture across 37.66–47%11 |
| 85 °C kiln finish | Character over enzyme survival | Where the goal is preserving enzymes, sorghum malt is kilned cooler. That is the correct choice for a malt that must convert its own starch. It is the wrong one for ours |
The kiln line is the clearest statement of what this standard is. Same grain, opposite temperature, because the conversion strategy differs — and a regime that kilns cool is not making an error, it is answering a different question.
Malting temperature is an end-use decision, not a property of the grain. The 30 °C / 25 °C split above, applied to the same hybrids for two different products, is the cleanest demonstration of that in the literature we surveyed.
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 and method on every enzymatic measure — °Lintner, °WK, ASBC, or SDU, never bare numbers, and never a unit without the method behind it. (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.
- Steep-out moisture, with its basis. Published work finds sorghum malt quality is directly related to the steep-out moisture of the grain11, and one study recorded it across 37.66–47%. A report that omits it leaves one of the most influential wet-process figures unstated.
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 (the panel method); 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.
How much cultivar choice actually moves
Ranking only earns its place if cultivars differ enough to matter. They do:
- Three- to four-fold variation in α-amylase and diastatic activity across 29 white-seeded cultivars in one published screen.10
- Two independent screens rejected most of their material against DP-first criteria — 8 of 24 and 5 of 26 passing. See Where diastatic power stands for what that means for an external-enzyme process.
- Cultivars respond differently to the same schedule. In our own 25-cultivar screening, a fourth germination day raised α-amylase in all 25 samples, by 19.2 DU on average across a 3.3 to 41.8 spread — while diastatic power barely moved, extract rose in 18 and fell in 7, and FAN rose in 20. The fourth day is an alpha-amylase decision, and what it buys depends on the cultivar.
Which is the argument for ranking rather than indexing. A single number cannot carry a response that differs by cultivar and by measure at once.
A worked ranking, from the only published pass/fail we found
The clearest published demonstration of a threshold-based ranking is not ours. Garzón and Drago (2018)4 screened 24 white and red sorghum hybrids and published the thresholds they applied.
| Element | As published |
|---|---|
| Material | 24 hybrids, white and red |
| Malting for the brewing assessment | 30 °C |
| Malting for the bio-functional assessment | 25 °C, same grain |
| Measures for brewing aptitude | Diastatic power · β-amylase activity · hot water extract · Kolbach index |
| Measures for bio-functional potential | GABA · free amino acids · phenolics · antioxidant capacity |
| Thresholds applied | ≥ 22 °DP/g d.b. and ≥ 60 UBetamyl/g d.b. |
| Result | 8 of 24 hybrids met both |
| Class finding | White hybrids showed better brewing potential |
A pass rate of one in three is what this screen found. Two thirds of a commercial hybrid set failed a two-part threshold, and the other published screen on this page rejected most of its material too.
The same grain was malted at two temperatures for two products — 30 °C for brewing, 25 °C for a bio-functional beverage. That is the cleanest evidence we found that malting temperature is an end-use decision rather than a property of the grain, and it is the reason this standard fixes a reference schedule before comparing anything.
And the thresholds are theirs, not ours. They are DP-first, which is the correct choice for a study asking whether sorghum malt can convert on its own — and the wrong axis for an external-enzyme process, where a hybrid failing ≥22 °DP/g might still produce the cleanest, best-tasting wort in the set. Same data, different ranking, because the conversion strategy differs.
Selecting sorghum: what to measure before malting
This standard evaluates malt, but the reason to evaluate malt is to choose grain. What follows is what a selection programme should carry into the reference mash.
What other regimes select on
Recorded because a reader choosing sorghum should know what criteria exist elsewhere, and which of them apply to an external-enzyme process:
| Regime | Selection criteria as stated |
|---|---|
| The Ghanaian screening panel (Komlaga et al. 2021, 26 varieties)5 | Germinative energy · green malt hydration · gelatinisation temperature · extract yield · limit attenuation · FAN · diastatic power |
| Industrial sorghum adjunct, West Africa | Uniform grain size and shape, round or oval · hard endosperm · higher extract · higher soluble protein · lower polyphenol and tannin · lower fat · low gelatinisation temperature |
| Baijiu, China | High amylopectin · moderate protein · low fat · tannin at an appropriate level rather than minimised |
| Farm-level selection, Burkina Faso | Red sorghum preferred for consistent sprouting during malting; varieties of medium amylase activity considered suitable |
Two of those regimes select on gelatinisation temperature. The Ghanaian panel is cited; the other three rows summarise regional practice gathered for this revision and are described qualitatively here until each carries a linked source.
Tannin, and the method for it
This standard assumes non-tannin sorghum, because condensed tannins bind the enzymes malting develops. That assumption has a citable method behind it: ISO 9648:19881 determines tannin content in sorghum grain by ferric ammonium citrate assay, and EAS 757:2011 applies it at a 0.5% maximum on whole grain, dry basis2. A report under this standard should state the tannin class of the material and the basis for it.
Gelatinisation onset — a proposed descriptive measure
We hold named-hybrid measurements: the K-State study reports sorghum gelatinisation onset at 61.75–65.51 °C, with substantial gelatinisation across roughly 68–81 °C (Gelatinization).
Why it matters for evaluation rather than only for process. The reference mash holds conversion constant — but only if gelatinisation has actually occurred. A sample whose starch gelatinises at the high end of that band, run against a fixed temperature program, can read as a poor malt when it is really an incompletely gelatinised one.
This is a proposal, not yet a requirement. Adding gelatinisation onset as a declared descriptive measure would let an adopting laboratory separate those two cases. We would rather hear from a lab on whether it is worth the instrument time before promoting it.
The reference mash, specified
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.
What would make this a real standard
Adoption, criticism, and iteration — in that order. Five specific pieces of work, smallest first. Every one produces a publishable result whether it confirms this draft or breaks it.
| # | The work | What it settles | Scale |
|---|---|---|---|
| 1 | Run the reference mash on any sorghum malt and report the friction (Ask 5) | Whether the enzyme doses, the 3.0 L/kg ratio and the temperature program are executable as written. So far it has only been checked on paper, by us | One bench, one day |
| 2 | Report a wort viscosity figure | The one required measure we could not supply a figure for from our own records or from the seven-region survey | One instrument, same session |
| 3 | Run the standard on a cultivar set with tannin class and gelatinisation onset declared | Whether gelatinisation onset separates a poor malt from an unconverted one — and whether it earns promotion from descriptive to required | A screening programme, one season |
| 4 | Validate the sensory lexicon | GFB-SML is drafted with definitions, a 0–15 scale and reference anchors. No panel has scored a malt set against it, and nine attributes still need a reference anchor | A trained panel, repeated |
| 5 | Re-screen cultivars a DP-gated study rejected | Whether any of the 37 cultivars set aside by the two published screens perform well under external enzymes. This is the question this standard was written to ask, and the survey behind this revision turned up no study framing it that way | A breeding programme with access to those lines |
Item 5 is the one that would change what gets planted. The University of Nevada, Reno program is building exactly the methodology this draft addresses.
And anyone publishing sorghum malt data can adopt the mandatory declarations even while rejecting everything else here. The declarations alone would fix half the field's comparability problem.
Version history
- v0.7 — 2026-09-13. Before merge, every outside claim was checked against its source and footnoted; the production-log turbidity stages were relabelled after the data showed stage C is fermented beer rather than kettle wort, with the high-gravity dilution between C and F noted; figures that could not be traced to a source were removed rather than left standing — the regional germination temperatures, a 50–60 °C kiln optimum, a 42–45% steep-out band, a total-starch range for baijiu sorghum, and a claim about sorghum FAN composition on which published work disagrees; the SDU figures were corrected to what the cited study reports; and the claim that ignoring diastatic power is the majority position was withdrawn. Restructured for use: a reader's entry table added; the diastatic-power position consolidated into one section rather than spread across the page, including a reconciliation of the °ASBC discrepancy against the r ≈ 0.97 method correlation; selection criteria lifted out of Principle 4 into their own section; gelatinisation onset added to the measures table as a proposed descriptive measure; the reference mash run sheet moved out of the argument; the open work stated as five ranked, scoped pieces.
- v0.4–v0.6 — 2026-09-13. Drawn from a seven-region survey of how sorghum is selected, malted and brewed. Expected-value ranges published for extract, FAN, DP and α-amylase from our 25-cultivar screening, with barley context; colour and pH added from the production log with a caveat on what they describe, and wort viscosity stated as having no figure; turbidity calibrated against 89 paired production samples including the FTU-90 basis limit; the reference malting schedule's four settings justified against the alternatives each trades away; conversion-strategy taxonomy added; two published cultivar screens and their pass rates added; steep-out moisture added as a sixth mandatory declaration. The "no good standard" claim was narrowed after a fresh search, which found ISO 9648:1988 for sorghum tannin, EAS 757:2011 as a three-grade East African grain specification, and EBC germinative-energy methods applied to sorghum — none of which evaluates sorghum malt for an external-enzyme process, which is the narrowed claim.
- 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.
Where this page comes from
This proposal synthesizes Bard's commercial malting and brewing experience, the USDA-ARS screening program's documented methods, a seven-region survey of published sorghum practice, 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.
Sources
Each outside source is named beside the claim it carries on this page; the footnotes hold the full citations. Figures from this site's own datasets link to those datasets directly.
Related
- Malting Sorghum Specification (GFB-MSS) — the companion: what grain is worth malting before this standard evaluates the malt
- Data Catalog — the datasets behind this proposal
- USDA Madison Screening — the 25-cultivar dataset behind the ranges above
- Production QA Log 2014–2017 — the turbidity pairs
- Cultivars for Malting — what named-cultivar evidence supports
- Gelatinization — the onset data
- SABS / SANS 235 — the SDU standard and its context
- Why Native Malt Enzymes Are Not Enough
- The Maltose Mash — the same spirit, applied to mash design
- Contribute Research