Sorghum Malting Protocol
Malt for character. Design conversion with external enzymes.
Native malt enzymes are a distraction. Ignore them. External enzymes own conversion.
No stage here is optimized to preserve native enzyme activity. Start from an accepted, protected, gluten-free-suitable lot — grain selection is owned by What Makes Good Malting Sorghum and storage and pre-malt viability by Grain Storage, Germination, and Mycotoxin Controls.
Flavor-First Sorghum Malting
- Protocol
- GFB-SM1
- Version
- Public 1.1
- Effective
- August 2026
GFB's selected working baseline for malting sorghum for character, developed from Bard's commercial gluten-free brewing experience. Values are a starting point to tune to your cultivar, equipment, water, and lot — not a universal specification. Start from an accepted, protected, gluten-free-suitable lot (see What Makes Good Malting Sorghum and Grain Storage). Native malt enzymes are deliberately ignored; external enzymes own conversion in the mash.
Critical: Run the steep and germination warm at a target of 82°F (28°C), and never let the bed reach 86°F (30°C) — above that, microbial pressure and uneven growth climb fast. Malt for flavor, not enzyme preservation. Hold and escalate any slime, sour or musty odor, heating, or mold; kilning is not a decontamination step.
Stage before grain-in
Hydrate the lot evenly and warm
- Do
- Run warm wet steeps separated by substantial air rests. Replace the water between steeps and aerate during them. Watch the grain, water, smell, heat, and uptake. Any warm-steep antimicrobial use follows your validated program and is fully rinsed out.
- Add
- Water changes between wet steeps
- Aeration during wet steeps
- Microbial control per your validated program (fully rinsed)
- Advance when
- The lot reaches steep-out — first chit showing, at roughly 33–36% moisture wet basis (52–58% if figured against dry grain weight), evenly, with no slime, sour odor, or heating.
- Record
- Steep and air-rest times · Water and grain temperature · Water changes and aeration · Uptake observations and the move-on or hold decision
Develop even modification
- Do
- Carry the warm condition from the steep. Manage airflow and temperature, and turn or manage the bed to keep growth even and prevent matting and internal heat. Spray water at the 8-hour checks to hold the bed near 41% moisture (wet basis) — sorghum, unlike barley, does not carry enough steep water to finish modification, so the watering is not optional. The spray rounds double as the microbial-observation cadence.
- Add
- Spray water at 8-hour checks to hold ~41% bed moisture (wet basis)
- Advance when
- Modification is even across the lot and the acrospire is roughly full kernel length. The acrospire is the endpoint, not the calendar: growth accelerates late (a ±~50% band in practice), and bed scale changes the timeline without changing the target.
- Record
- Start and end times · Temperature range and airflow · Turning events and spray rounds with bed-moisture checks · Growth, evenness, and any spoilage signs
Stabilize and build character
- Do
- Choose and run the validated kiln or roast path for the malt the beer needs — pale, toasted, amber, or roasted. Do not protect native enzyme activity. The Bard’s working baseline: 40°C for 10 h, 54°C for 4 h, 60°C for 3 h, 68°C for 2 h, 85°C for 3 h — full schedule and reasoning on the kilning page.
- Add
- None
- Advance when
- The malt reaches its intended character and is dried and stabilized to about 4–5% moisture.
- Record
- Kiln/roast path and targets · Temperature path and time · Finished moisture · Color and sensory character
QA and release the finished lot
- Do
- Inspect visually and test separately: gluten, and the mycotoxins your hazard analysis identifies. Use a representative sampling plan and suitable methods. Homogenize only lots that each independently pass. Blending is never corrective action.
- Add
- None
- Advance when
- Every documented finished-malt acceptance criterion is met, with batch identity, retained samples, and traceability recorded — then release to a controlled brewing trial only.
- Record
- Inspection findings, recorded separately from lab results · Full QA panel by batch ID · Retained-sample and component/homogenization records · The release decision and its basis
Prove it in beer
- Do
- Screen mash and wort behavior, run a controlled external-enzyme mash, and evaluate fermentation and finished beer.
- Add
- None
- Advance when
- The malt supports acceptable milling, mash behavior, wort, fermentation, flavor, aroma, body, color, drinkability, and repeatability.
- Record
- Screening and mash behavior · Fermentation performance · Finished-beer sensory result · Scale, repeat, restrict, or reject decision
| Step | Action | Target | Add | Advance when |
|---|---|---|---|---|
| 1. Steep: more detail | Run warm wet steeps separated by substantial air rests. Replace the water between steeps and aerate during them. Watch the grain, water, smell, heat, and uptake. Any warm-steep antimicrobial use follows your validated program and is fully rinsed out. | 82°F (28°C) target — never let the grain reach 86°F (30°C) 2–3 wet steeps ~8 h + air rests |
| The lot reaches steep-out — first chit showing, at roughly 33–36% moisture wet basis (52–58% if figured against dry grain weight), evenly, with no slime, sour odor, or heating. |
| 2. Germinate: more detail | Carry the warm condition from the steep. Manage airflow and temperature, and turn or manage the bed to keep growth even and prevent matting and internal heat. Spray water at the 8-hour checks to hold the bed near 41% moisture (wet basis) — sorghum, unlike barley, does not carry enough steep water to finish modification, so the watering is not optional. The spray rounds double as the microbial-observation cadence. | 82°F (28°C) target — bed never reaches 86°F (30°C) ~4–5 days at production scale; small bench beds can finish in ~3 |
| Modification is even across the lot and the acrospire is roughly full kernel length. The acrospire is the endpoint, not the calendar: growth accelerates late (a ±~50% band in practice), and bed scale changes the timeline without changing the target. |
| 3. Kiln: more detail | Choose and run the validated kiln or roast path for the malt the beer needs — pale, toasted, amber, or roasted. Do not protect native enzyme activity. The Bard’s working baseline: 40°C for 10 h, 54°C for 4 h, 60°C for 3 h, 68°C for 2 h, 85°C for 3 h — full schedule and reasoning on the kilning page. | Your flavor/color target (working baseline finishes at 85°C / 185°F) Working baseline: ~22 h across five stages, plus ~30-min ramps | None | The malt reaches its intended character and is dried and stabilized to about 4–5% moisture. |
| 4. Release: more detail | Inspect visually and test separately: gluten, and the mycotoxins your hazard analysis identifies. Use a representative sampling plan and suitable methods. Homogenize only lots that each independently pass. Blending is never corrective action. | All acceptance criteria met Per your QA program | None | Every documented finished-malt acceptance criterion is met, with batch identity, retained samples, and traceability recorded — then release to a controlled brewing trial only. |
| 5. Prove: more detail | Screen mash and wort behavior, run a controlled external-enzyme mash, and evaluate fermentation and finished beer. | Acceptable finished beer Trial + evaluation | None | The malt supports acceptable milling, mash behavior, wort, fermentation, flavor, aroma, body, color, drinkability, and repeatability. |
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.
Hydrate the lot evenly and warm
Objective
Bring the whole lot to even, useful moisture to start germination — without souring, heating, sliming, or hydrating unevenly.
Operating instruction
Run warm wet steeps separated by substantial air rests. Replace the water between steeps and aerate during them. Watch the grain, water, smell, heat, and uptake. Any warm-steep antimicrobial use follows your validated program and is fully rinsed out.
- Water changes between wet steeps
- Aeration during wet steeps
- Microbial control per your validated program (fully rinsed)
What good looks like
The lot reaches steep-out — first chit showing, at roughly 33–36% moisture wet basis (52–58% if figured against dry grain weight), evenly, with no slime, sour odor, or heating.
Watch for
Slime or biofilm, sour or musty smell, grain heating, foul water, visible mold, or fractions hydrating unevenly.
If this happens
Hold or stop the lot and follow your validated nonconformance and food-safety procedure. Do not improvise a chemical treatment. See Microbial Control During Warm Steeping for the risk decisions.
Record
Steep and air-rest times · Water and grain temperature · Water changes and aeration · Uptake observations and the move-on or hold decision
Level 3 · Mechanism and evidence Steeping Sorghum
Develop even modification
Objective
Grow even, useful modification for the beer — not maximum rootlet growth and not maximum enzyme development.
Operating instruction
Carry the warm condition from the steep. Manage airflow and temperature, and turn or manage the bed to keep growth even and prevent matting and internal heat. Spray water at the 8-hour checks to hold the bed near 41% moisture (wet basis) — sorghum, unlike barley, does not carry enough steep water to finish modification, so the watering is not optional. The spray rounds double as the microbial-observation cadence.
- Spray water at 8-hour checks to hold ~41% bed moisture (wet basis)
What good looks like
Modification is even across the lot and the acrospire is roughly full kernel length. The acrospire is the endpoint, not the calendar: growth accelerates late (a ±~50% band in practice), and bed scale changes the timeline without changing the target.
Watch for
Matting, overheating in the bed interior, weak or uneven growth, or mold, slime, or off odor. Late-germination overshoot drives batch-to-batch variation — the reason accepted lots are later homogenized.
If this happens
For heat, matting, or uneven growth with no spoilage signs, adjust airflow, turning, or cooling per your procedure. For mold, slime, off odor, or contamination, hold and escalate — do not aerate it back into production.
Record
Start and end times · Temperature range and airflow · Turning events and spray rounds with bed-moisture checks · Growth, evenness, and any spoilage signs
Level 3 · Mechanism and evidence Germinating Sorghum
Stabilize and build character
Objective
Stop growth, reduce moisture, stabilize the malt, and create the intended flavor and color. Kiln for character — native enzymes are not preserved.
Operating instruction
Choose and run the validated kiln or roast path for the malt the beer needs — pale, toasted, amber, or roasted. Do not protect native enzyme activity. The Bard’s working baseline: 40°C for 10 h, 54°C for 4 h, 60°C for 3 h, 68°C for 2 h, 85°C for 3 h — full schedule and reasoning on the kilning page.
What good looks like
The malt reaches its intended character and is dried and stabilized to about 4–5% moisture.
Watch for
Unstable, uneven, scorched, harsh, off-odor, or misclassified malt.
If this happens
Hold or restrict malt that is off-target or misclassified. Kiln temperatures and paths are owned by the kilning page — set them there for the character you want.
Record
Kiln/roast path and targets · Temperature path and time · Finished moisture · Color and sensory character
Level 3 · Mechanism and evidence Kilning and Roasting for Character
QA and release the finished lot
Objective
Decide whether the finished malt lot may enter a controlled brewing trial — a safety, gluten-free, identity, and traceability judgment against documented criteria.
Operating instruction
Inspect visually and test separately: gluten, and the mycotoxins your hazard analysis identifies. Use a representative sampling plan and suitable methods. Homogenize only lots that each independently pass. Blending is never corrective action.
What good looks like
Every documented finished-malt acceptance criterion is met, with batch identity, retained samples, and traceability recorded — then release to a controlled brewing trial only.
Watch for
A lot that looks fine but carries gluten cross-contact or mycotoxins, an unrepresentative sample, or pressure to blend a failing lot into passing material.
If this happens
Hold under your nonconformance procedure; restrict only under a separately authorized disposition; otherwise reject. If in doubt, toss it out.
Record
Inspection findings, recorded separately from lab results · Full QA panel by batch ID · Retained-sample and component/homogenization records · The release decision and its basis
Level 3 · Mechanism and evidence Finished Sorghum Malt QA and Lot Release
Prove it in beer
Objective
Determine whether a safety-released malt performs well enough to scale or repeat — after release, not instead of it.
Operating instruction
Screen mash and wort behavior, run a controlled external-enzyme mash, and evaluate fermentation and finished beer.
What good looks like
The malt supports acceptable milling, mash behavior, wort, fermentation, flavor, aroma, body, color, drinkability, and repeatability.
Watch for
Treating a good beer as a safety result.
If this happens
A successful trial proves performance; it cannot erase a safety, gluten-free, identity, traceability, custody, or regulatory failure. Such a lot remains nonconforming.
Record
Screening and mash behavior · Fermentation performance · Finished-beer sensory result · Scale, repeat, restrict, or reject decision
Level 3 · Mechanism and evidence The Reliable Mash: Enzyme Mash
After The Run
The lot met every finished-malt acceptance criterion.
- Visible inspection and lab results (gluten, hazard-based mycotoxins) both pass.
- Batch identity, retained samples, and traceability are recorded.
- Only independently-passing lots were homogenized.
- Release is to a controlled brewing trial — not to routine use or sale.
Do not push a suspect lot forward.
For slime, sour or musty odor, heating, or mold at any stage, hold under your nonconformance and food-safety procedure. Kilning is not a decontamination step, and a later good beer does not cure a safety failure. Contamination decisions are owned by Microbial Control During Warm Steeping.
The warm steep that builds flavor also favors bacterial and fungal growth. Control it deliberately with clean incoming grain, water changes, air rests, aeration, and observation. In Bard's commercial experience, food-grade hydrogen peroxide was one part of that program — used food-grade and rinsed out completely, not because it is harmless. No product identity, concentration, dose, or contact time is published here. Any current use must meet applicable law and good manufacturing practice, remove residual peroxide during processing, and follow a validated facility procedure; under 21 CFR 173.356 (as amended effective September 3, 2025) hydrogen peroxide may be used as an antimicrobial agent in accordance with GMP with residual removed. That framework states conditions; it does not validate a process, authorize a dose, or address mycotoxins. See Microbial Control During Warm Steeping.
The Records Chain
source lot → acceptance → storage → steep → germination → kiln/roast → finished-malt QA → retained samples → external-enzyme brewing trial → scale, restrict, hold, or reject
- Steep and air-rest times, water and grain temperature
- Water changes, aeration, and uptake observations
- Steep-out condition and the move-on or hold decision
- Start and end times, temperature range, airflow, turning
- Growth, evenness, and any spoilage signs
- Acrospire state at move-on
- Kiln/roast path, temperature path, and time
- Finished moisture, color, and sensory character
- Inspection separate from lab results; full panel by batch ID
- Retained samples, component/homogenization records, release decision
- Brewing-trial screening, fermentation, and finished-beer result
Technical Basis And Open Questions
Technical basisThese are one operation's selected working values, not multi-trial specifications.
The steep and germination conditions and endpoints come from Bard's commercial gluten-free brewing program — the 82°F (28°C) operating target and the 86°F (30°C) never-reach line are the same rule read from both sides, and the steep-out and bed moisture targets match the program's own quality standards. The kiln schedule was developed with guidance from John Taylor (University of Pretoria) and Allen Budde. GFB publishes all of it as a selected working baseline to start from and tune — not as a universal specification, and not as a diastatic-power-optimized process. Native enzymes are deliberately ignored; external enzymes own conversion.
Open questionThe germination endpoint is a wide band, and that variability is real.
Modification is judged by acrospire development to roughly full kernel length, but growth accelerates in late germination and can overshoot — a ±50% band in practice. That batch-to-batch variability is a large part of why independently-passing lots are later homogenized at QA. Scale is part of it: small, well-aerated bench beds reach the endpoint in about 3 days while production beds take 4–5, which is why the acrospire — not the calendar — is the endpoint. The steep-out moisture target has since been recovered from the program's own quality standards (~33–36% wet basis); a validated germination window per cultivar and equipment set remains the open work.
Mechanism And Evidence
Controlled hydration, air rests, water changes, and the move-on or hold decision.
RiskMicrobial control during warm steepingWhy warm steeping raises the pressure, the warning signs, and the stop decision.
GerminateRun the germination stageEven modification, airflow and temperature, drift and failure signs.
KilnKiln and roast for characterStabilize the malt and design flavor and color — not enzyme preservation.
ReleaseFinished-malt QA and lot releaseInspect, test, homogenize correctly, and make the release decision.
WhyWhy native malt enzymes are not enoughThe conversion doctrine behind ignoring native enzymes.