SABS 235: The Standard the Field Borrowed, and Why It Doesn't Fit
This page supports: the proposed Sorghum Malt Evaluation Standard (GFB-SME) — the review of the incumbent that the proposal answers.
What SABS 235 is
SABS Method 235 was established by the South African Bureau of Standards in 1970, for determining the diastatic power of malts prepared from kaffircorn (sorghum), including bird-proof varieties, and from millet. Its unit — the Sorghum Diastatic Unit (SDU) — is South Africa's official measure of sorghum malt diastatic power, and it descends from the foundational kaffircorn malting research of L. Novellie and colleagues at South Africa's CSIR in the 1950s–60s, the work that first put sorghum malting on a laboratory footing.
The context that shaped it: South Africa's traditional opaque-beer industry, a large commercial sector brewing sour, cloudy, actively-fermenting beer in which sorghum malt performs the conversion. In that product, diastatic power is the commercially decisive property — the malt is bought and sold on it. A DP-first standard for that industry is a correct standard.
What it measures — and what it never asks
SABS 235's core is the SDU diastatic assay: a measure of the malt's joint amylase activity. As the trading standard for opaque-beer malt, the surrounding specification concerns itself with conversion capacity and basic grain quality.
What it never asks is everything a modern gluten-free brewer needs to know:
- Wort clarity and turbidity — irrelevant to an intentionally opaque product; decisive for ours.
- Flavor and aroma contribution — opaque beer's character comes largely from souring and active fermentation; a clear lager wears its malt character naked.
- Foam, stability, packaged shelf life — opaque beer is consumed young and alive; nothing in a 1970 opaque-beer spec contemplates a canned product with a nine-month shelf life.
- Performance in an external-enzyme process — the entire premise of modern gluten-free brewing at scale, and the exact premise SABS 235 inverts.
The units problem it exported
Because SDU is its own unit system, sorghum DP results exist in SDU, °Lintner, °Windisch-Kolbach, and ASBC units depending on which lab borrowed which method — and they do not interconvert cleanly. It's telling that the Journal of the Institute of Brewing published a study specifically on the convertibility of IoB, EBC, and SABS methods for sorghum DP1 — a paper that only needs to exist because the field's central measurement is fractured across incompatible systems. Our own 2002–2004 dataset carries a DP column whose units died with the worksheet. This is why GFB-SME makes units declarations mandatory.
Why borrowing it was rational, and why it should stop
For decades, a lab handed sorghum malt and asked "is this good?" had three options: barley methods that measure sorghum's deficits, SABS 235 which measures a property modern brewing deliberately doesn't use, or improvisation. Reaching for the one sorghum-shaped standard on the shelf was reasonable. But every borrowed use quietly imported the opaque-beer premise — malt as enzyme engine — into work on products where external enzymes own conversion and the malt's job is character. Cultivar screening ranked DP champions; breeding programs optimized for a number the target process ignores; and the measures that actually decide whether a sorghum beer is drinkable — clarity, flavor, FAN — rode in the back seat when they rode at all.
The respectful summary: SABS 235 is a good standard for the product it serves. The problem was never the standard — it was the vacuum around it. The GFB-SME draft is our attempt to fill that vacuum with something built for the job.
The paper trail
- The foundational method work — L. Novellie's kaffircorn malting and brewing studies (CSIR, Journal of the Science of Food and Agriculture series, 1959–1968) established the sorghum malt assays SABS 235 codified.
- The convertibility study — the IoB/EBC/SABS sorghum DP methods comparison, Journal of the Institute of Brewing (2004).1
- The modern review — Taylor et al. (2013) covers sorghum brewing science including the opaque-beer tradition and its enzyme-first framework.2
- The screening benchmark — the 16-cultivar Cereal Chemistry survey (1995) shows DP-first evaluation applied to cultivar screening.3
Source and Validation Notes
This review describes SABS/SANS 235 from the published literature around it, not from the standard's text — national standards are copyrighted documents, and this page characterizes rather than reproduces. Specific claims about the standard's establishment date, unit system, and scope come from the published method-comparison and review literature cited above. If you hold the current SANS 235 text and find this characterization wrong anywhere, that's exactly the correction we want.