Traditional Home Scale Milling Techniques for Pulses

Dal is central to the Indian plate – eaten daily across households in countless forms, from simple arhar dal with rice to spiced chana preparations. But before any pulse reaches the cooking pot, it must be milled: the tough outer husk removed, the grain split into the familiar cotyledons we know as dal. While large-scale commercial mills handle most of this processing today, the home scale method of milling – using basic tools like a mortar and pestle or a hand-operated stone mill – has fed rural communities across India for generations. Understanding how this process works, step by step, helps explain why it persists and what makes it uniquely suited to household-level food processing.

What is home scale pulse milling? 🔗

Home scale pulse milling refers to processing pulses at the household level using simple, locally available tools – without mechanized or industrial equipment. It is practiced widely in villages across India, particularly where access to commercial mills is limited or where households process small quantities of pulses for immediate consumption. The method is not uniform: it varies by region, by pulse type, and by available resources. What remains consistent is the underlying logic – loosen the husk first, then remove it.

Pulse milling at any scale involves two fundamental steps: (i) loosening of the seed coat or husk, and (ii) dehusking and splitting of the grain. At the home scale, both steps are carried out manually, relying on physical effort and basic tools rather than machinery.

Step 1: Loosening the husk 🔗

The husk of most pulses does not detach easily from the cotyledon without some prior treatment. Loosening it is therefore the first and most critical stage of the process. At the home scale, this is done through either a wet method or a dry method – or a combination of both.

Wet method (water treatment) 🔗

In the wet method, cleaned pulses are soaked in water for 2 to 8 hours. For pulses that are relatively easy to dehusk, plain water soaking is sufficient. For more resistant varieties – such as pigeon pea (arhar), black gram, and green gram – the soaked pulses are sometimes mixed with red earth (a mild abrasive clay) before drying. The red earth helps loosen the husk further and imparts a characteristic yellow colour to the finished dal. After soaking, the pulses are spread out in the sun to dry before dehusking begins.

Dry method (oil treatment) 🔗

In the dry method, oil is applied to the cleaned pulses – typically around 150 to 250 grams of oil per 100 kg of pulses. The oil is worked into the grain surface and the pulses are then stored overnight. As the oil seeps between the husk and the cotyledon, it breaks the adhesion between the two layers, making the husk significantly easier to remove. A small amount of water – around 2.5 to 3.5 kg per 100 kg of pulses – may be applied additionally and the pulses left overnight, which helps loosen the husk further. The following day, the pulses are sun-dried before milling.

Sun drying is an economical and essential part of the process. Pulses are spread over a floor or rooftop in layers of 5 to 7.5 cm and stirred periodically. This drying makes the husk brittle and facilitates clean separation during dehusking.

Step 2: Dehusking using mortar and pestle or chakki 🔗

Once the husk is adequately loosened and the pulses are dried, the actual dehusking takes place. At the home scale, two tools are primarily used: the mortar and pestle (called okhli-musal in Hindi) and the hand-operated stone mill (called chakki).

Mortar and pestle 🔗

The mortar and pestle is the most common tool for home-scale dehusking when the quantity to be processed is small – typically up to 5 kg at a time. Dehusking happens through a combination of shearing action between the pestle and the grains, and abrasive contact between individual grains. A key structural advantage of the mortar is its deep bowl shape, which confines the grain and prevents spillage – a practical benefit over flat grinding stones when working with small quantities.

The process is not a single continuous pounding. After each round of pounding, the loosened husk and split cotyledons are separated from whole (still-husked) grains by manual sieving and winnowing – tossing the material in a shallow basket so that the lighter husk blows away. The remaining whole grains are pounded again. This cycle repeats until the desired level of dehusking is achieved.

It is worth noting that dal yield from mortar and pestle processing is relatively low – around 50 to 60% – due to breakage and chipping of cotyledon edges during pounding. This is a known limitation of the method.

Hand-operated stone mill (chakki) 🔗

For larger quantities, villagers use the hand-operated wooden or stone chakki. The chakki consists of two abrasive stones – a stationary lower stone, slightly convex, and a rotating upper stone, slightly concave, with a central hole through which grains are fed. As the upper stone is turned using a wooden handle, the grain tumbles between the two abrasive surfaces, which simultaneously dehulls and splits it. Continued turning reduces the split grain to flour if needed. The chakki gives better throughput and more consistent results than the mortar and pestle for larger batches, though the technique and pre-conditioning of grains remains essentially the same.

Regional variations: how the method adapts 🔗

One of the defining features of home scale milling is how strongly it is shaped by local conditions. The method is not the same across India – it adapts to the pulse being processed, the available tools, and regional preferences.

Uttar Pradesh and Madhya Pradesh: arhar and gram 🔗

These two states are among India’s most significant pulse producers. Gram, urad, and arhar are the principal pulses grown in both Madhya Pradesh and Uttar Pradesh, making home-scale processing of these varieties particularly common in rural households here.

For arhar (pigeon pea), the dry oil treatment is frequently preferred. Mustard oil – widely available in northern India – is worked into the grain, followed by overnight storage and sun drying before dehusking. In some households, the oil-treated and dried pulses are lightly roasted in a heavy pan before milling. This additional step makes the husk more brittle, facilitating easier removal, and also develops a slightly nutty flavour in the finished dal.

For gram (chickpea), a water-steeping variation is commonly employed. Cleaned chickpeas are soaked in water, then dried before dehusking. In some households, the steeping step is extended, with partially softened grain being dried and then milled – a variation that shortens cooking time later and can improve digestibility of the finished product.

Other regional adaptations 🔗

Across India, the method continues to evolve based on local pulses and climate. Women typically soak seeds and then allow them to sit overnight or for several hours in the sun before pounding, which helps distribute moisture evenly through the grain – a principle consistent across many pulse-growing regions. In areas with high ambient humidity, drying periods may be extended. Some households use salt water for soaking certain pulses, while others incorporate fermentation steps for varieties like black gram and green gram, which also aids digestibility.

Limitations of home scale milling 🔗

Home scale milling is practical and accessible, but it has well-documented limitations. The method is labour-intensive and time-consuming, and dal recovery rates are lower than with mechanized processing. Breakage of cotyledons during pounding is significant, and the appearance of the finished dal is less uniform compared to mill-processed product. These limitations largely explain why commercial dal mills – which use roller dehuskers, emery rollers, and controlled tempering – have replaced home-scale processing for most households with market access.

That said, home scale milling remains relevant where commercial mills are not accessible, where households process small quantities, or where specific regional preparations call for it. The method also retains knowledge of pulse-specific treatments – the right oil quantity, soaking duration, and drying time for each variety – that is directly useful even in semi-mechanized cottage-scale settings.

Why this method still matters 🔗

Home scale milling is more than a fallback in the absence of machinery. It encodes practical, grain-specific knowledge about how different pulses respond to water, oil, heat, and abrasion. Understanding the two-step logic – husk loosening followed by mechanical separation – is foundational to understanding pulse milling at any scale. The same core principles of pre-conditioning and dehusking that govern home-scale processing are scaled up in commercial and cottage-industry operations. The tools change; the logic does not.

For agricultural students and food technology practitioners, the home scale method offers an accessible entry point into understanding pulse processing – one where every step can be observed and adjusted by hand, without the complexity of industrial machinery.

What do you think? Given that home scale milling results in 50-60% dal yield compared to higher recovery rates in mechanized mills, should rural households be supported with affordable small-scale dehusking equipment rather than continuing with traditional methods? And how much of the regional variation in pulse processing – different oils, soaking times, roasting steps – reflects genuine technical optimization versus cultural preference?

References

1. https://kcpelearning.com/showcourse/pulse/intro-to-pulse-milling
2. http://sambasivamagri.blogspot.com/2010/03/milling-of-pulses.html
3. https://www.aesmofoodmachine.com/pulse-process/
4. https://course.cutm.ac.in/wp-content/uploads/2020/06/Session-4.4-%E2%80%93-Pulse-Milling.pdf
5. https://en.wikipedia.org/wiki/Mortar_and_pestle
6. https://www.researchgate.net/publication/287312732_Pulse_Milling_Technologies
7. https://tractorkharido.com/news/india-pulses-production-types-and-major-states
8. https://www.appropedia.org/Analysis_of_the_various_types_of_mills/Traditional_methods_of_grinding_grain
9. https://www.kviconline.gov.in/pmegp/pmegpweb/docs/commonprojectprofile/Dalmill.pdf