Driven  to near extinction by mechanised screw and hydraulic presses of  factories, the indigenous "ghani" technology still lives on in the hands  of one man at Bhetgari of Rangpur's Kishoreganj upazila.

This correspondent came upon Birol while he was working one of his two horses in his setup by the road last month.

The  ghani works combining a circular stone mortar, an angled wood pestle  and weights. As the horse moves in a circular path, the pestle rotates,  exerting pressure on the pit, first pulverising the mustard seed and  then crushing out its oil.

Because of insufficient pressure,  yields are about 5 per cent less than in modern expellers, which can  churn out one kilogramme of oil from every 2.5 kg mustard seed.  Traditional  ghanis have a maximum capacity of about 50 kg per day, and modern  powered units only about twice that much, says a Food and Agriculture  Organization paper.

Moreover, trained animals are needed. They  are expensive to feed and require rest. Artisan training is also  essential. Birol was seen continuously turning over the seeds while  working the press. As a result, running costs are disproportionately  high.

According to the Department of Agricultural Extension, some  7.87 lakh tonnes of mustard seed were produced in fiscal 2020-21 from  around 5.89 lakh hectares of land.

In fiscal 2019-20, it was 7.50 lakh  tonnes from 5.68 lakh hectares of land.

Still every year, some  2.5 lakh to 3 lakh tonnes of mustard seed are imported. Currently, the  annual demand for mustard oil stands at 1.5 lakh tonnes.

The residue of the crushed seeds is known as oil cakes. They are sold at Tk 30 a kg as animal feed.

While  online shops sell branded and non-branded mustard oil in the range of  Tk 240 to Tk 280 per litre, Birol sells his for Tk 360. He says his  customers include people from Rangpur Cantonment, all seeking purity.

He  believes his assurance of the product being pure and made right before  their eyes would continue to ensure sales in spite of the high price.