But one Australian start-up is deploying artificial intelligence to speed up the process, which it claims could take just six minutes.
The company, called Cropify, is also among the first in the world to commercialise grain-grading technology and plans to set its sights on bigger tasks in future: chickpeas, faba beans and international expansion.
The company is part of a growing agrifood tech industry in Australia, which AusTrade estimates attracts $800 million in investment each year.
Fifth generation farmer Anna Falkiner founded the business with husband Andrew Hannon in 2019, before generative AI started making headlines.
Grading grain had consistently proven challenging for farmers, she said, due to the time it took to complete and the staff required to complete it.
"We're using a combination of machine-learning and hardware to crack a long-standing pain point for the grain industry," Ms Falkiner told AAP.
"This way you're not reliant on a whole lot of casuals who haven't had a lot of training and you know you're getting the same quality of grading all the time so it's objective, fair and accurate."
Graders typically inspect 200 grams from each parcel of grain, looking for signs of damage, mould, loose coatings, insect infestations, contrasting colours and foreign seeds.
Each grain is given a rating based on this assessment, which sets its price.
The Adelaide-based company initially tried to create AI software to assess grains, Ms Falkiner said, but realised hardware would be needed to ensure the process remained consistent.
The resulting product, Cropify Opal, looks like a printer but features patented trays to load grains into the machine, two high-powered cameras to capture them, and uploads images to the cloud to be processed by AI software.
Testing did reveal one unexpected problem, she said: the AI-powered machine was often a tougher judge than humans.
"Obviously, we don't want our product to be so tough that it changes the grading system that's already in place," she said.
"We decided to benchmark ourselves against professional, full-time, grain-grading specialist humans."
While the company chose red lentils as its first target, the machine would be updated to grade desi chickpeas early next year, Ms Falkiner said, followed by faba beans, sorghum and other grains.
The company raised $2 million from venture capital partners in 2024, and plans to launch another capital-raising shortly.