Quick answer: The reference method in the FSSAI manual is oven drying. A grated sample of about 3 g is mixed with prepared sand and dried in a forced-air oven at 102°C (controlled to ±1°C) until two weighings agree within 0.5 mg. It takes several hours. A rapid moisture analyser gives a result in minutes and suits routine batch checks, but you must validate it against the oven method on your own paneer. Record every test against a batch number so any drift can be traced.
Why measuring comes first
You can’t adjust pressing or chilling if you don’t know what your blocks actually contain. This article covers how to measure moisture. Target ranges and fixes for blocks that come out wrong are in our guide to improving paneer quality in production.
Two ways to test
| Oven drying (reference method) | Rapid moisture analyser | |
|---|---|---|
| How it works | Weigh, dry in an oven, weigh again | Heats the sample while a balance tracks weight loss |
| Time | About 4 hours in the oven, plus preparation and re-drying cycles | Minutes per sample |
| Best for | Reference, dispute and compliance testing | Routine batch checks |
| Needs | Forced-air oven, balance, desiccator, dishes, prepared sand | The analyser, plus a validation study |
| Main risk | Slow, so problems are found late | Reads all volatiles lost, not only water |
The oven method, step by step (FSSAI 2022 manual)
The FSSAI 2022 paneer moisture method (01.043:2022) uses the same procedure as its cheese moisture method (01.039:2022). It measures the loss in mass when the sample is heated in an air oven at 102 ± 2°C to constant mass.
Safety: use thermal gloves, tongs and eye protection. Slide the desiccator lid open gradually, because a vacuum can form as hot dishes cool.
- Prepare the sample. In the FSSAI 2015 manual, this means grating the paneer quickly, mixing it thoroughly, and keeping it in an airtight container below 10°C until analysis. Test it as soon as possible.
- Prepare the dish. Heat a flat-bottom dish holding about 20 g of prepared sand and a glass rod in the oven for about an hour. Cool it in a desiccator for 30–40 minutes. The sand passes a 500 µm sieve and is retained on a 180 µm sieve. It is acid-digested, washed, dried and ignited to dull red.
- Weigh in about 3 g of the prepared paneer.
- Mix with sand. Wet the sand with a few drops of distilled water, mix the sample through it and spread it evenly over the bottom of the dish.
- Water bath. Place the dish on a boiling water bath for 20–30 minutes, then wipe the bottom of the dish.
- Oven. Dry the dish uncovered in a forced-air oven controlled at 102 ± 1°C for about 4 hours.
- Cool and weigh. Cover the dish, cool it in a desiccator to 25 ± 3°C, and weigh to the nearest 0.1 mg.
- Repeat. Dry for another hour, cool and weigh again. Continue until two successive weighings differ by 0.5 mg or less.
- Calculate. Moisture % by mass = (M1 − M2) ÷ (M1 − M) × 100, to the nearest 0.01%. M is the empty dish with its sand and glass rod, M1 is the dish with lid, rod, sand and sample before drying, and M2 is the same after drying.
The 2022 edition refers to a separate sample-preparation method (FSSAI 01.042:2022). Confirm with your lab that its manual edition matches the steps above.
Using a rapid moisture analyser
An analyser heats a small sample with a halogen or infrared lamp and tracks the weight loss on a built-in balance. In a study on processed cheese, an infrared analyser averaged about 9 minutes per sample, against about 4 hours for the sand-and-oven reference method. Its results differed from the reference by 0.14–0.30 points of total dry mass. That study was on cheese, not paneer, so don’t assume the same figures hold for yours.
Before you rely on one:
- Validate it against the oven method. The cheese study had to validate the drying temperature and sample mass, and found 110°C worked best for those products. Find the settings that work for your paneer.
- Run both methods side by side. Analyser makers suggest a short comparison can show whether the two agree. Use samples from several batches.
- Know what it measures. An analyser reports everything lost at its drying temperature, not only water.
- Don’t mix methods on one trend line. Keep oven and analyser results in separate columns.
Which method to use, and when
- Every batch, in-process: the validated rapid analyser.
- Periodic verification: run the oven method on a retained sample alongside the analyser.
- Disputes, audits or contract questions: the reference oven method, or an accredited lab.
- After any change (new milk source, press adjustment, maintenance, new operator): test more often until readings settle.
Taking a good sample
- Grate and mix the sample before weighing, as the FSSAI manual says.
- Take it from more than one position in the block so it represents the whole piece. This is a practice tip, not a step from the manual.
- Test promptly and keep the sample sealed and cool.
How often to test and what to log
No standard in the sources we reviewed sets a testing frequency, so treat the following as a starting point to write into your own food safety plan:
- A rapid check on every batch.
- Oven-method verification on a fixed interval that you choose and record.
- Extra tests after any process change.
Log these fields for every test:
| Field | Why it matters |
|---|---|
| Date and batch number | Links the result to dispatched product |
| Milk source and type | Spots source-related drift |
| Press and chilling settings | Links results to process changes |
| Sample position | Shows variation across a block |
| Method (oven or analyser) | Keeps results comparable |
| Result | The core record |
| Operator and action taken | Shows what was done about it |
Common mistakes
- Leaving the grated sample uncovered or warm before testing.
- Using an analyser without validating it against the oven method.
- Comparing oven and analyser readings as if they were the same series.
- Leaving the sand out of the empty-dish mass (M) when calculating.
- Logging results without batch numbers.
- Running one test a week and assuming it represents every batch.
Frequently asked questions
What is the standard oven method for paneer moisture in India?
The FSSAI 2022 paneer method (01.043:2022) refers to its cheese method (01.039:2022). A sample of about 3 g is mixed with prepared sand and dried in an oven at 102°C, controlled to ±1°C, until successive weighings agree within 0.5 mg.
How long does the oven method take?
About 4 hours in the oven after a 20–30 minute water-bath step, plus repeat 1-hour cycles until the weights agree.
Can a rapid moisture analyser replace the oven method?
For routine in-process checks, yes, once you have validated it against the oven method on your own paneer. Keep the oven method for reference, disputes and compliance testing.
Why do oven and analyser results differ?
They use different heating, temperatures and sample sizes, and an analyser records everything lost at its drying temperature. A side-by-side comparison shows how far apart they are for your product.
How often should I test?
Set it in your QA plan. A reasonable starting point is a rapid check on every batch, with oven verification on a fixed schedule you record.
Conclusion
Use the oven method as your reference and a validated rapid analyser for daily checks. Log every result with a batch number, and keep the two methods in separate columns so trends stay trustworthy.
Consistent pressing makes consistent readings. If you are choosing a press for your volume, see our paneer making machine range or contact our team.
Sources
- FSSAI, Manual of Methods of Analysis of Foods: Milk and Milk Products (2022): methods FSSAI 01.039:2022 (moisture in cheese) and FSSAI 01.043:2022 (moisture in channa/paneer).
- FSSAI, Manual of Methods of Analysis of Foods: Milk and Milk Products (2015), section 5 (channa or paneer).
- “Accuracy of drying selected products using a moisture analyzer method based on infrared radiation” (processed cheese study).
- Mettler Toledo, white paper “Drying Oven vs. Halogen Moisture Analyzer”.