Bitter, musty atta after 45 days in a Bikaner chakki

Two separate spoilage mechanisms are running at once, and 100% extraction feeds both.

Bitter-soapy note - lipid degradation. Wheat germ contains roughly 10% oil, rich in unsaturated fatty acids, plus active lipase and lipoxygenase. In a 100% extraction atta the germ is milled through the whole flour, so every particle carries oil and enzyme. Two reactions follow:

• Hydrolysis (lipase): triglycerides → free fatty acids, which taste soapy and bitter. Requires water, so 13.5% flour moisture and monsoon humidity drive it.
• Oxidation (lipoxygenase/auto-oxidation): unsaturated acids → hydroperoxides → hexanal, 2-pentylfuran and similar volatiles, the 'paint-like' end of the same story.

Musty 'khadi' smell - mould. Flour held above roughly 13% moisture in warm humid air supports Aspergillus and Penicillium, giving musty, earthy off-notes and, in the worst case, mycotoxins.

Why temperature and packaging multiply it: packing at 38–40 °C into a woven PP bag (no moisture barrier) over a damp floor against an outside wall creates a moisture gradient - the wall side cools at night, water condenses, and the local moisture climbs. Every 10 °C rise roughly doubles the reaction rate, and June–July in western Rajasthan supplies both heat and humidity. Tribolium (red flour beetle) is the predictable third guest: it thrives at 25–35 °C and above about 10% moisture, and woven bags are not insect-proof. Fifteen-day-old atta is fine because none of these reactions has had time to accumulate.

Milling and finishing

• Finish the flour at 12.5% moisture or below (temper for milling, then verify the flour, not the wheat).
• Cool the flour to below 30 °C before packing - a simple holding bin or pneumatic conveying with ambient air will do; do not pack 40 °C flour into a bag.
• Stabilise the germ fraction: either steam/heat-treat before milling, or reduce extraction to about 90–95% and divert some germ, or degerm before grinding. Each option buys shelf life at a nutritional cost.

Packing

• Move from woven PP to a laminated moisture-barrier pouch (BOPP/PE or metallised laminate) with a proper seal; that single change removes the condensation cycle and blocks insect entry.
• Print batch, date of manufacture and best-before on every bag; run FIFO.

Storage

• Pallets at least 10–15 cm off the floor and 45 cm from walls; nothing stacked against an outside wall.
• Godown below 25–30 °C and below 60% RH; insulate or ventilate the tin roof, or shift the finished-goods store to a cooler room.
• Monthly pest monitoring with traps, crack-and-crevice cleaning, and only approved fumigants/insecticides used by trained staff - never sprayed onto flour.
• Realistic commercial rule: dispatch within 30–40 days in summer, 60 days in winter, and design the pack for the worse case.

Trade-off: 100% extraction keeps the bran, fibre, minerals and B vitamins that customers want, but it also keeps the germ and its enzymes and oil. You cannot sell an unmodified 100% extraction stone-chakki atta with a 60-day summer shelf life in a woven bag. Choose: keep the nutritional claim and invest in heat stabilisation, cooling and barrier packing; or accept a shorter shelf life and a smaller distribution radius. Say which, and price accordingly.

His current atta does not qualify. 'Fortified' is a defined claim, not a marketing word.

Formulation

• Add a premix supplying, per the +F standard for atta: iron (about 28–42 mg/kg), folic acid (about 75–125 µg/100 g) and vitamin B12 (about 0.75–1.25 µg/100 g). Verify the current schedule and the exact permitted levels with FSSAI before printing anything.
• Buy premix only from an approved supplier, with a certificate of analysis and a batch number; store it cool, dry and dark, and use it within its shelf life.

Process control points

• A volumetric or gravimetric doser at the flour stream with a locked setting - hand-scooping into a 2-tonne day's output cannot give uniform distribution.
• Adequate blending/conveying after dosing so a 5 kg bag is representative of the batch.
• Iron premix (ferrous fumarate/sulfate) can catalyse rancidity, so the cooling and barrier-packing fixes above become more important, not less.
• Retain a sample per batch and send periodic samples to a NABL-accredited laboratory for iron, folic acid and B12; keep the reports for the tender file.

Legal and labelling

• Appropriate FSSAI licence covering fortified atta manufacture, with the fortification endorsement.
• The +F logo on the pack, plus the mandatory declarations: FSSAI licence number, ingredient list including the premix, nutritional information per 100 g, batch, date of manufacture, best before, net quantity, storage instructions and customer care details.
• Do not print 'fortified' until the first analytical report confirms the levels - an unverified claim is both a tender disqualification and a regulatory violation.

Without a doser, a barrier pack and laboratory verification, he should decline the tender rather than promise a specification he cannot control.