How Much Sorghum Malt a Batch Uses
What Bard's batches used
| Batch | Malt | Per barrel | Gravity |
|---|---|---|---|
| 42-barrel (49 hL) production brew, May 2020 | 2,300 lb (1,043 kg) | About 55 lb (21 kg/hL); 4.0 lb (1.8 kg) a case | Flagship, median 11.2 °P across 2014–2017 |
| 60-barrel (70 hL) recipe, December 2018 | 3,750 lb (1,700 kg) | About 62 lb (24 kg/hL) | Recipe still being finalized |
| 5-gallon (19 L) homebrew batch | 10 lb (4.5 kg) | About 62 lb (24 kg/hL) | About 10.3–11.4 °P at 70% efficiency (worked below) |
A barrel here is a US beer barrel, 31 US gallons (117 L). The production figures are from Bard's record, as recorded (How Big Is the US Gluten-Free Malt Market?); the homebrew batch is The Reliable Mash at Homebrew Scale. The flagship's gravity is from the 2014–2017 production log, and the 2016 procedure specified 10.5 °P (Production QA Log).
Why the figures differ
Efficiency. A production brewhouse gets more extract out of the same malt than a homebrew kettle does, so it needs less malt for the same gravity. A better brewhouse needs less malt.
Gravity. Malt scales with the gravity you brew to. A beer at 13 °P takes about a fifth more malt than one at 11 °P on the same system.
The malt itself. Extract varies from lot to lot. The three 2019 production malts ran 66.8%, 68.8% and 76.8% fine-grind extract, dry basis, an eight-point spread between two of them (Reading a Malt COA). Size every new lot from its own certificate. Sorghum malt is scarce, and a batch sized on last lot's numbers can come up short on gravity.
A recipe in progress. The December 2018 figure was set while the contract recipe was still being finalized; the May 2020 brew is the settled one.
Work it out for your batch
Two steps: the extract your beer needs, then the malt it takes to get it.
1. The extract your beer needs.
- US units: extract (lb) = gallons × 8.345 × specific gravity × °P ÷ 100
- Metric: extract (kg) = litres × specific gravity × °P ÷ 100
2. The malt it takes. Divide the extract by three numbers: the malt's fine extract (dry basis, from the certificate), its dry matter (1 minus the moisture on the certificate), and your brewhouse efficiency.
Worked once, on one barrel at Bard's flagship gravity. One barrel is 31 gallons (117 L). At 11.2 °P, specific gravity 1.045, the beer needs about 30 lb (13.7 kg) of extract. On the 2019 white malt, 76.8% extract and 7.4% moisture, at 75% efficiency, that's 30 ÷ (0.768 × 0.926 × 0.75), about 57 lb of malt a barrel (22 kg/hL). Bard's May 2020 brew used about 55.
Turned around, Bard's own figure implies an efficiency. At 55 lb a barrel (21 kg/hL) and 10.5–11.2 °P, the two 2019 production malts with full panels put Bard's brewhouse at roughly 72–86% efficiency, depending on the lot. That's derived arithmetic on recorded figures, so measure your own.
At homebrew scale, the same arithmetic runs the other way. 10 lb (4.5 kg) of those malts in 5 gallons (19 L), at 70% efficiency, lands at about 10.3–11.4 °P, which matches the flagship's range.
Run it for your batch
Enter your batch and your gravity, and the calculator sizes the malt, scales the Maltose Mash (or the Reliable Mash) to it, and scales the American Golden Lager recipe to the batch, with the hops, the tetra swap and the gypsum open to change. Add your own prices if you want a batch cost. It's version 1.0: if you need it to do something it doesn't, tell us and we'll be happy to accommodate it.
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What the arithmetic leaves out
- Rice hulls. They're runoff structure added at mash-out, not extract, so leave them out of the malt weight. Start near 5% of malt weight on a new system (Rice Hull Strategy).
- A blended grist. If sorghum is only part of the grist, size each malt for its own share of the extract.
- Enzymes. Doses are set per pound of malt, so they follow the malt weight. The rates are on The Reliable Mash.
- Losses after the mash. Kettle, trub and fermenter losses change how much wort you need at the start. Size from the volume you collect, and record which volume you used.
Before your first production batch
Prove a new lot small before it goes into a production brew (Starting Small with Sorghum Malt), and record your real efficiency from the first batch on (Pilot to Production). Once you have a few batches recorded, size from your own numbers.
Need malt, or looking to malt? Contact us. Very little sorghum malt is made, and what's on the market may not meet your needs. We're working to change that, putting brewers and maltsters together. Tell us what you brew, or what you malt, and roughly how much a year.
If you need help
We consult on gluten-free beer top to bottom, and as far as we've found, we're one of very few who cover all of it: the grain and the malthouse, the recipe and the mash, the QA chain, and packaging, release and shelf life (Consultation). If you need help with any of it, reach out. The first conversation costs nothing.
Next step
- Ready to write the order? Use Ordering Sorghum Malt.
- Reading a new lot's numbers? Start with Reading a Malt COA.
- Scaling up? See Pilot to Production.