For centuries, indigenous edible oils have been an integral part of our culture, deeply intertwined with our culinary heritage. Among these oils, mustard oil, extracted by traditional cold-pressed methods, has played a pivotal role in our kitchens. This time-tested technique not only sustained small-scale processing but also provided employment for generations, fostering local procurement and distribution networks with minimal carbon footprint. It was a sustainable system, creating a virtuous cycle for our communities.

However, in the name of health benefits and the pursuit of ‘heart-healthy’ options, two unnatural fats—Vanaspati ghee and refined oil—were introduced to South Asia. These newcomers had a profound impact on our socio-cultural cooking and consumption patterns.

Vanaspati ghee, once marketed as a healthier alternative under the name ‘Dalda,’ underwent a transformation. Edible oil was hydrogenated, a process that involved adding hydrogen to convert liquid unsaturated fats into solid saturated fats, resulting in vanaspati ghee. It resembled ghee in appearance and boasted a higher melting point, making it ideal for deep frying. On the other hand, refined oils, touted as purer and capable of ‘producing good cholesterol,’ were virtually odorless, colorless, and tasteless. They were primarily solvent-extracted.

This introduction was a deliberate attempt to undermine indigenous and unprocessed oils while promoting the importation of less healthy options, including Palm oil, one of the unhealthiest oils globally, and other refined oils. This shift nearly led to the extinction of our ‘Kol’ or cold pressing mills and eroded the traditional knowledge of mustard oil production.

Fortunately, a new awareness is emerging among Nepali, prompting them to return to their roots and embrace the use of mustard oil. Mustard oil possesses a distinct and robust flavor with pungent and slightly bitter notes. This unique flavor complements the spices and herbs commonly used in pickles, resulting in a well-rounded taste profile that is challenging to replicate with other oils.

In traditional Newari cuisine, quick-marinated delicacies like choyela, kachila, and aloo cha rely on mustard oil to balance the flavors of cumin, garlic, and ginger. These dishes require no additional seasoning when the perfect combination of sourness and heat is achieved with salt and mustard oil.

In pickle recipes with only a few ingredients, the quality of each component becomes paramount. Using pure, high-quality mustard oil ensures that it enhances the overall flavor and aroma of the pickle. Adulterated mustard oil mixed with other oils can negatively impact the taste and aroma. Back in the day, most mustard oil was locally produced, guaranteeing its purity.

Mustard oil offers numerous health benefits. For centuries, it has been used to alleviate colds, coughs, and respiratory issues. Inhaling steam with mustard oil can clear respiratory congestion, and massaging a mixture of mustard oil, garlic, and ajwain on the feet and chest may provide relief from cold and cough.

Mustard oil contains glucosinolates, which contribute to its antibiotic, fungicidal, and cancer-prevention properties. It may protect against colorectal and gastrointestinal cancers. Allyl isothiocyanate, found in mustard oil, acts as an antifungal agent and can protect food from fungal growth.

The nutritional profile of mustard oil may support the health and strength of red blood cells. When applied topically, mustard oil can cause a warming sensation and increase blood flow, potentially alleviating pain. It has traditionally been used as a rubefacient and irritant. Some individuals use mustard oil topically to relieve joint pain and arthritis symptoms, thanks to its warming and soothing effects.

Mustard oil is believed to boost immunity, possibly due to its anti-inflammatory and antioxidant properties. It’s also considered suitable for diabetes recipes due to its anti-inflammatory properties. Additionally, it’s said to stimulate the appetite and may slow the growth of cancer cells.

One of the remarkable qualities of mustard oil is its ability to act as a natural preservative for pickles. It helps bind the spices and dried fruits together, allowing them to absorb the seasoning, which contributes to the authentic flavor of the pickle. Mustard oil also contains compounds such as allyl isothiocyanate, which possess powerful antimicrobial, antifungal, and antibacterial properties. The oil forms a protective coating, sealing off access to oxygen and preventing spoilage, thereby extending the shelf life of the pickle.

Pure mustard oil has low water activity, which means it contains minimal dissolved water. This property inhibits the growth of bacteria and fungi, preserving the quality and flavor of the pickle.

Roasted mustard oil, known as ‘bhuteko tori ko tel’, is another indigenous variety produced in different mustard oil pressing mills in Kathmandu Valley. Unlike the cold-pressed variety, roasted oil undergoes a dry-roasting process that softens its raw mustard flavor, resulting in a dark amber-colored oil. This variation is particularly used in dishes like choyela.

Mustard oil production in Nepal is not just an industry; it’s a way of life. It celebrates agriculture, culture, and culinary traditions. The significance of mustard oil in Nepali households and its enduring presence in the heart of Nepali cuisine cannot be understated.

Mustard oil is not merely an ingredient but a culinary and cultural treasure of Nepal. It enhances flavor, preserves pickles, provides health benefits, and carries cultural significance in many culinary traditions, particularly in Nepal. Its unique qualities make it an essential component in the pickling process, and its role goes beyond the kitchen.

Mustard oil is a symbol of our heritage, connecting us to our roots and reminding us of the rich traditions that continue to shape our culinary experiences. As we celebrate the resurgence of mustard oil in our kitchens, we also celebrate our cultural heritage and the flavors that make Nepali cuisine truly special.

The author is a UK-based R&D chef

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