Food
Routine quality-control instruments for food and beverage laboratories: colour, moisture, sample mass, acidity and sodium.
In short
Most food and beverage specifications are covered by five measurements: colour or absorbance, moisture, sample mass, pH or acidity, and sodium or potassium. A single-beam spectrophotometer, a halogen moisture analyser, a 1 mg balance and a pH meter form the core; a flame photometer is added where sodium or potassium is a declared value.
The routine tasks behind a typical quality programme, the parameters involved and the instrument group that covers them.
| Measurement task | Parameters / range | Typical method | Instrument group |
|---|---|---|---|
| Colour and absorbance | 0–2 Abs · 340–1000 nm | Colorimetry at fixed or scanned wavelengths | UV-Vis spectrophotometer |
| Moisture / loss on drying | 0.1–100 % | Halogen or infrared drying to constant mass | Moisture analyser |
| Sample and standard weighing | 0.001 g | Gravimetric | 1 mg balance |
| pH and titratable acidity | pH 0–14 · 0.1–20 % acid | Direct measurement or titration | pH meter / titrator |
| Sodium and potassium | 0.1–100 mg/L in solution | Flame photometry | Flame photometer |
| Vitamin and additive absorbance | µg/mL to mg/mL | Colorimetric or spectrophotometric | UV-Vis spectrophotometer |
| Turbidity and clarity | 0–1000 NTU | Nephelometry | Turbidity meter |
| Water content in selected matrices | 0.01–5 % | Volumetric Karl Fischer titration | Karl Fischer titrator |
Workflow
Most results are decided before the instrument is switched on. These are the steps where laboratories usually lose accuracy.
Colour, moisture and acidity mean different things in different product standards.
Grinding, mixing and subsampling cause more variation than the instrument does.
Dilution changes the matrix; record the factor and stay inside the curve.
Duplicate preparations, not duplicate readings, show whether the method is under control.
Moisture and colour drift with temperature and humidity; record them with the result.
Start from a complete configuration rather than a single instrument: the supporting units decide whether the workflow runs without interruption.
Primary configuration
A single-beam spectrophotometer with the wavelength range for colour work, additive assays and routine absorbance.
Double-beam stability matters only if the protocol demands long unattended runs.
Primary configuration
Halogen drying with a built-in balance: the fastest routine route to a loss-on-drying result.
Loss on drying is not water content; matrices with volatile components need Karl Fischer.
Primary configuration
1 mg readability covers sample and standard preparation for most food methods.
Reference-standard work at 0.1 mg needs the next model up.
Supporting
pH, conductivity and ion measurement for acidity and process water checks.
Not a titrator; titratable acidity needs a burette or an automatic titrator.
Supporting
Sodium and potassium as declared values without an atomic absorption bench.
Element-specific: it does not replace AAS for trace metals.
Entry / alternative
A second moisture analyser for a second product line or a busier shift.
Same principle as the DSH; choose by throughput and pan size.
Entry / alternative
Entry-level single beam for laboratories doing colour work only.
Limited headroom if a method later needs scanning or a wider range.
Method detail, common errors and configuration choices, written for this workflow.
Application note
The five measurements that cover most food and beverage specifications, the instruments that deliver them, and when a…
Application note
Why homogenisation, portion size and holding time often decide whether a food result transfers between laboratories — and…
Application note
A method-first guide to fixed-wavelength colour tests and routine absorbance work in food QC, including when a colorimeter…
Food and beverage quality control is a repeatability problem before it is a sensitivity problem. Two laboratories with the same instrument get different results mainly because they grind, mix and subsample differently — so the first investment is a documented sample-preparation routine, not a better detector.
The five-measurement core covers a surprising share of declared specifications. Colour and absorbance handle appearance and many additives; moisture handles the most common compositional claim; sample mass underpins every calculation; pH or acidity covers preservation and taste; sodium and potassium cover the mineral declarations on most labels. A laboratory that can do these five reliably can usually add product-specific methods without another bench.
Where the specification talks about water content rather than loss on drying, or the product contains alcohol or volatile oils, the drying method will over-report. That is the point at which a Karl Fischer titrator earns its bench space — not as an upgrade, but as a different measurement.
Food testing starts with the product specification and the way a sample moves through the bench. Record the sampling point, homogenization step, portion size and holding time before comparing instruments.
For an export project, describe the products, declared values, expected batch volume, local standards and report language. The configuration can then combine UV-Vis, moisture, weighing, titration and elemental measurements without leaving sample preparation as an afterthought.
Short answers; send the details of your method for a definite reply.
Loss on drying measures everything that evaporates; Karl Fischer measures water. If the specification states water content, or the matrix contains alcohol or volatile oils, use Karl Fischer.
Only when the protocol requires reference-beam stability over long runs, or the laboratory runs unattended sequences. Routine colour and absorbance work is well served by single beam.
Cost and stability. 1 mg covers sample and standard preparation for most methods; 0.1 mg is for reference standards and small weighed portions.
Yes, if the wavelength range covers both. Colour work often sits at fixed wavelengths, while vitamin assays usually need a scan and a calibration curve.
For sodium and potassium, yes. Calcium, magnesium, iron and trace metals need atomic absorption or another elemental technique.
Let’s talk about your application
Send your matrix, target parameters and reference method for a configuration review.
