USDA 2023: Sorghum Grain Protein by NIR — Handheld vs. Benchtop

92 sorghum grain samples from the 2021 Kansas and Texas harvest, protein measured by combustion nitrogen and predicted by two near-infrared instruments — a benchtop laboratory unit and a handheld field unit. Published by the USDA-ARS grain quality program as U.S. public-domain data; mirrored here because two of its facts matter to every gluten-free brewer: sorghum grain protein spans 6.4 to 16.8%, and screening it no longer requires a laboratory.

This is an external dataset. The record of authority is the USDA deposit on Ag Data Commons — doi:10.15482/USDA.ADC/1529552, license U.S. Public Domain. This page mirrors it unchanged and adds the brewing-side reading; the originating work is Bean, Peiris, and Wu at the USDA-ARS Grain Quality and Structure Research Unit (Manhattan, Kansas), with the companion open-access paper by Peiris, Bean, Wu, Sexton-Bowser, and Tesso in Foods (2023), doi:10.3390/foods12163101 (CC BY 4.0).

Explore this data

Sort, filter, and plot measured against predicted values. The full tables below remain the printable, citable record; this is the same data, interactive.

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Methods, briefly

• Samples: 2021-harvest grain — test-market hybrids from private seed companies and public breeding programs grown at dryland sites in Assaria, Kansas and Sunray, Texas, an irrigated site in Colby, Kansas, plus samples from a Manhattan, Kansas breeding program.
• Reference measurement: combustion nitrogen (LECO FP-828p, AACC method 46-30.01), N × 6.25, reported as-is moisture basis.
• Instruments compared: a Perten DA-7250 benchtop NIR and a VIAVI MicroNIR OnSite-W handheld, spectra collected on intact grain.
• Design: 59 samples built the calibrations; 33 held-out samples tested them. The deposit carries both sets; this mirror merges them into one CSV with a sample_set column and changes nothing else.

What these numbers mean for brewing

• Sorghum grain protein is a lot-level variable, and the spread is wide. 6.4 to 16.8% across one harvest year — a 2.6× range. Grain protein is the upstream driver of soluble protein and FAN in the malt, and FAN is the sorghum brewer's designed input (yeast nutrition): the Hartwick production malts ran 46–87 mg/L FAN partly because of where their grain sat on exactly this kind of spread. A brewer or maltster who doesn't know their lot's protein is guessing at the nutrition problem before the mash starts.
• Screening no longer requires a laboratory. The study's point is instrumental: the benchtop unit predicted combustion protein at R² ≈ 0.95, and the handheld — a field instrument — at R² ≈ 0.89, both with mean absolute error under 0.6 protein points on held-out samples. The authors' conclusion is that the handheld is acceptable for screening intact grain. For a craft maltster sorting incoming sorghum lots, that is the difference between sending samples away and sorting at the truck.
• The honest limits. This dataset predicts protein and nothing else — not diastatic power, not FAN, not extract. It is grain, not malt. And screening precision (±0.6 points) is sorting precision, not specification precision — a declared laboratory value on a certificate is still the number a contract should reference, which is exactly the declarations discipline GFB-SME requires.

Summary statistics

Computed from the dataset as deposited (mean absolute error and r² against the combustion reference; the paper reports its own validation statistics of R² 0.94 / RMSEP 0.52% for the benchtop and R² 0.87 / RMSEP 0.76% for the handheld):

Set	n	Protein range, %	Benchtop MAE, pts	Benchtop r²	MicroNIR MAE, pts	MicroNIR r²
Calibration	59	6.41 – 16.76	0.30	0.977	0.46	0.945
Validation	33	8.16 – 16.22	0.43	0.949	0.59	0.892

The dataset

Protein content, % (g/100 g grain), as-is moisture basis. Values exactly as deposited.

Calibration set (59 samples)

Measured, %	Benchtop NIR, %	MicroNIR, %
13.09	13.08	13.44
11.18	11.21	11.28
12.42	12.39	12.30
13.44	13.38	13.35
12.13	12.22	12.87
10.97	11.11	10.89
7.14	7.63	7.52
11.58	11.87	12.17
11.86	11.84	12.54
10.29	10.65	10.24
10.77	10.33	10.55
11.37	10.88	10.50
9.70	9.56	10.03
11.09	11.06	10.32
9.61	9.37	9.33
11.68	11.71	11.61
12.55	12.63	12.84
12.03	12.54	11.63
9.77	9.55	9.51
16.76	15.68	14.75
14.94	15.33	14.88
6.96	7.31	6.96
7.03	7.12	6.59
8.18	8.23	8.13
7.24	7.49	7.66
6.41	6.32	6.51
7.76	7.36	7.62
8.28	7.99	7.87
8.61	8.41	8.72
7.95	7.80	8.13
7.43	7.44	7.37
15.72	14.88	14.85
6.82	6.48	6.71
8.20	8.17	8.08
12.29	12.19	12.77
9.00	8.62	8.35
7.48	7.77	7.83
12.07	12.03	11.63
11.42	11.86	11.67
10.37	9.93	10.25
11.01	10.29	10.23
11.21	11.04	11.54
12.94	13.10	13.26
11.61	11.52	12.17
11.77	12.34	12.61
10.78	10.65	10.58
8.74	9.19	10.41
15.66	15.99	16.31
6.73	7.29	7.84
6.97	6.99	7.33
8.25	8.52	7.59
7.86	7.84	7.78
7.26	6.92	6.49
8.03	7.81	7.71
15.94	15.64	14.77
8.40	8.59	8.50
14.87	15.84	15.14
7.16	8.53	8.87
8.18	7.50	7.15

Validation set (33 samples)

Measured, %	Benchtop NIR, %	MicroNIR, %
13.79	13.97	13.55
14.22	14.70	14.61
12.95	13.33	11.81
10.76	10.28	9.39
12.98	12.56	11.37
13.22	12.97	12.20
12.65	12.17	12.72
11.18	11.30	11.45
9.55	10.11	9.82
11.55	11.88	11.21
8.94	8.71	8.72
9.76	10.42	9.70
9.11	8.80	8.81
9.62	10.02	9.73
10.47	11.77	10.98
11.50	11.82	12.12
14.58	15.21	15.33
14.55	15.07	15.67
12.05	12.88	13.35
14.61	14.70	14.93
13.83	14.69	15.36
16.22	15.87	15.01
14.76	15.30	15.45
12.02	10.78	10.66
10.25	10.01	10.21
12.76	12.97	13.08
13.39	13.59	13.67
8.16	7.80	7.49
11.79	12.34	12.32
13.33	13.26	13.01
10.75	11.12	10.68
8.58	8.48	8.75
9.37	9.19	9.17

Download

→ Download as CSV — both sets merged, sample_set column added, values unchanged.

The canonical files live in the USDA deposit: Ag Data Commons, doi:10.15482/USDA.ADC/1529552. This dataset is not separately archived on Zenodo — it already has a permanent federal DOI, and a second archive would add noise, not persistence.

Record

Mirrored and first published on this site 2026-08-11. Corrections to date: none. Because this is an external record, corrections split two ways: an error in our mirror or reading notes is ours — report it here and it gets logged in this section. An error in the data itself belongs upstream — report it to the originating authors via the Ag Data Commons record, and if the deposit is revised, this mirror follows it (logged here).

How to cite this dataset

Cite the originating deposit, not this page:

Bean, S.R., Peiris, S., Wu, S. Data from: Performance of a handheld Micro NIR instrument in comparison with laboratory benchtop NIR instrument for determining protein levels in harvested sorghum grain samples. USDA Ag Data Commons, 2023. https://doi.org/10.15482/USDA.ADC/1529552

For the analysis behind it: Peiris, K.H.S., Bean, S.R., Wu, X., Sexton-Bowser, S.A., Tesso, T. Performance of a Handheld MicroNIR Instrument for Determining Protein Levels in Sorghum Grain Samples. Foods 12(16):3101, 2023. https://doi.org/10.3390/foods12163101

If the brewing-side reading here was useful, this page can be cited as: Gluten Free Brewer, "USDA 2023: Sorghum Grain Protein by NIR," 2026, https://glutenfreebrewer.com/research/external/usda-2023-sorghum-protein-nir

Related

• Yeast Nutrition — why grain protein matters downstream: FAN is the sorghum brewer's designed input
• Hartwick 2019 Malt Analysis — what production sorghum malt protein and FAN actually looked like
• Sorghum Malt Evaluation Standard (GFB-SME) — the declarations discipline that turns screening numbers into contract numbers

Source and Validation Notes

Mirrored programmatically from the two CSV files in the USDA deposit (calibration, 59 rows; validation, 33 rows) on 2026-08-11: files downloaded from the deposit's own download URLs, merged with a sample_set column, byte-order marks and empty annotation columns removed, no value changed. The deposit's license is U.S. Public Domain; the mirror and these notes carry this site's usual CC BY 4.0. The originating laboratory is named because the work is published federal research; no endorsement of this site by USDA-ARS or the authors is implied.