SABS / SANS 235: The Opaque-Beer Standard
Part of the Evaluation Methods survey.
What it 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, descending from the Novellie / CSIR assay 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
The core is the SDU diastatic assay: the malt's joint amylase activity, plus basic grain-quality specification for opaque-beer malt trading. What it never asks is everything a modern gluten-free brewer needs: wort clarity and turbidity (irrelevant to an intentionally opaque product), flavor and aroma contribution, foam and packaged stability (opaque beer is consumed young and alive), and performance in an external-enzyme process — the premise SABS 235 exactly inverts.
The units problem it exported
Because SDU is its own 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. The Journal of the Institute of Brewing published a study specifically on the convertibility of IoB, EBC, and SABS sorghum DP methods1 — a paper that only needs to exist because the field's central measurement is fractured. Our own 2002–2004 dataset carries a DP column whose units died with the worksheet.
The verdict
For decades, a lab handed sorghum malt 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 rational — and every borrowed use quietly imported the opaque-beer premise into work on products where external enzymes own conversion. SABS 235 is a good standard for the product it serves. The problem was never the standard — it was the vacuum around it.
Source and Validation Notes
This review characterizes SABS/SANS 235 from the published literature around it, not from the standard's text — national standards are copyrighted documents, and this page describes rather than reproduces. If you hold the current SANS 235 text and find this characterization wrong anywhere, that is exactly the correction we want.