A bilona is a wooden churn used in Indian homes to turn curd into butter: an upright wooden beater stands in a pot of curd, held by a stand or post, and a rope wound round its shaft spins it first one way, then the other. The spinning breaks open the fat globules in the curd so their fat clumps into grains of makkhan. That butter is what bilona ghee is clarified from.
This article is about the tool and the physics of what it does. For the whole method from milk to jar, read the bilona process, step by step. For doing it in your own kitchen, see our guide on how to make bilona ghee at home.
At a glance
- A bilona is an upright wooden beater in a pot of curd, held by a stand or post and spun one way and then the other by a rope wound round its shaft; Punjab calls it a madani and Haryana a rai.
- Churning shears the fat globules until their membranes tear and the leaking fat glues them into grains; once the clumps reach about 52 micrometres the emulsion breaks and butter separates.
- Sour curd churns more easily because acidity weakens the globule membrane; a 1973 study put the best dahi acidity at 0.9 to 1.1 per cent.
- A hand churn applies little shear and recovers only 75 to 78 per cent of the fat in the makkhan; the rest stays in the buttermilk.
- No study we found compares a wooden bilona with an electric churner for yield or flavour; the physics is the same in both.
What is a bilona, exactly?
A bilona is a hand churn: a wooden beater that sits in a pot of curd, a rope wound round the beater's shaft, and a stand or post that supports the beater over the pot. Pulling the rope turns the beater. Under various regional names, it is used in Indian village households to make makkhan.
The Vernacular Furniture of India project, run by the Design Innovation and Craft Resource Centre at CEPT University with the South Asian Decorative Arts and Crafts Collection Trust in the UK, records two such churns, both made of wood and cotton rope.
- Madani, from Amritsar in Punjab: a churner "used to churn butter or curd to make buttermilk", with a stand to hold the churner and a base to keep the pot upright. "A rope is wound around the churner which is used to turn it."
- Rai, the common name for a churner in Haryana: the one recorded was supported from a wooden post in a verandah with cotton rope and used to churn in a terracotta pot. The pot sat on a ring made of rice stalk so that it stayed upright while churning.
Bilona is another name for this kind of churn, and the one that gives bilona ghee its name. Himdhara's butter is churned on one: whole milk is set into curd overnight with a native starter, churned on a wooden bilona, and the butter is clarified slowly over a wood fire.
How does the rope-and-stick action work?
The person churning pulls on a rope wrapped round the beater's shaft. Because the rope circles the shaft, the pulls turn the beater in alternate directions, first one way and then back. A stand or a post supports the beater so that it stays upright in the pot while it turns.
The 2021 review of makkhan production in the Journal of Food Science and Technology, from IIT Delhi and the West Bengal University of Animal and Fishery Sciences, describes the older household practice. In the early hours of the morning, the dahi is churned in an earthen pot "with a wooden beater by moving it in alternate direction with help of a special arrangement made by circling a thick rope on the body of the beater".
The same review notes three working habits that go with the tool.
- Churn in the morning. The review says the cool early morning is preferred, and that makkhan is churned at room temperature, which is warmer than the temperature used for butter.
- Add water as you go. Dahi is diluted with water at different stages of churning. In total, roughly as much water as dahi goes in, which the review links to getting the most makkhan.
- Lift the butter off the top. The fat floats on the surface of the churned curd and is collected in small lumps.
What happens to the fat when curd is churned?
Milk fat sits in tiny globules, each wrapped in a thin membrane. Churning shears the globules. Their membranes tear, liquid fat leaks out and glues partly solid globules together, and the clumps grow until the fat separates from the watery part as butter grains.
The makkhan review sets out the sequence, drawing on butter research. During ripening, some of the fat inside each globule crystallises, and the crystallised globules start to clump once the mixture is sheared. In churning, "fat globule membranes are ruptured and liquid fat leaks out to create a semisolid connection between globules." The clumps keep growing. When their average size reaches a critical value of about 52 micrometres, the emulsion breaks down, grains start to form, and the water phase begins to separate out.
Food scientists call the end point phase inversion. As a 2024 paper in JDS Communications from Aarhus University and Arla Foods explains, cream is an oil-in-water emulsion, with fat droplets in water. Churning turns it into butter, a water-in-oil emulsion, with water droplets held in fat. In that study the authors drained off the buttermilk after phase inversion, before churning again, to stop it being worked back into the butter.
A 2013 study in the Journal of Dairy Science, also from Aarhus University, churned cream in a laboratory rheometer and detected phase inversion as a change in viscosity. Cream ripened at 10 °C for five hours gave larger butter grains than unripened cream, 91 against 52 micrometres, and half an hour of ripening cut churning time from 22.9 to 16.2 minutes. These studies used cream, not curd; the makkhan review draws on the same cream research to explain how dahi churns.
Why does sour curd churn into butter more easily?
Acidity weakens the film around each fat globule. The makkhan review says that "as pH decreases the film surrounding the fat globules becomes weaker and churning becomes easier." So sourer dahi churns more easily, but the review warns that curd which is too sour gives makkhan with poorer texture and a shorter keeping life.
The review cites a study by Rangappa and Achaya (1973). It found that dahi with an acidity of 0.9 to 1.1 per cent gives good quality makkhan and the highest yield. Above that range churning is quicker and the yield is no lower, but the makkhan cannot hold its texture and keeps much less well.
Temperature matters too, the review notes. At a low churning temperature, around 5 °C, more of the fat in each globule is solid, so it is harder to squeeze out and churning takes longer. Above about 13 °C a larger share of the fat is liquid and churning is quicker. Larger globules, over about 5 micrometres, form butter grains more easily than small ones.
How much fat does a hand churn leave in the buttermilk?
The makkhan review reports that in the traditional method about 14 kg of mixed cow and buffalo milk makes 1 kg of makkhan; that is a butter figure, not a ghee one. Only 75 to 78 per cent of the fat is recovered in the makkhan; the remaining 22 to 25 per cent goes into the chhach, or buttermilk.
The review also notes that traditional churning applies little shear and "cannot rupture all the fat globules", which continuous industrial churns break down completely. That fits the mechanism above, since fat only joins the butter once its globule has been broken open, but the review does not say how much of the lost fat it accounts for.
How does a wooden bilona compare with an electric churner?
An electric churner does the same job with a motor instead of a rope. The makkhan review records that household churning today is done in a specially designed metal container with drainage, using a beater that is either wooden or motor-driven. The physics does not change: shear tears the globule membranes.
On the hand churn's limits, the review says that because the set-up is simple and cheap, process control is not possible in a traditional churn. To improve makkhan it suggests batch machines with controls for cooling, ageing, churning speed and temperature, and continuous butter machines for large-scale production when cream rather than dahi is used.
| Churn | How it turns | What it churns | Control over the process |
|---|---|---|---|
| Wooden bilona (rope-turned) | By hand, in alternate directions, via a rope round the shaft | Dahi in an earthen or terracotta pot | None built in; the review says parameters cannot be controlled |
| Motor-driven beater | Electric motor | Dahi, in household practice in a metal container with drainage | Depends on the machine; the review gives no details for household units |
| Batch mechanised churn (proposed) | Motor | Proposed for makkhan; the review's wording refers to cream churning | Controls for cooling, ageing, speed and temperature |
| Continuous butter machine | Motor, continuous flow | Cream | Industrial; breaks down all fat globules, per the review |
Two honest caveats. We found no study comparing a hand bilona with an electric curd churner for yield, flavour or the ghee that follows, and no test of the claim that the two-way hand motion makes better ghee. And the review says no scientific intervention had improved makkhan making since it began; much of the science above comes from cream butter. How ghee from curd differs from ghee made straight from cream is a separate question, covered in our comparison of bilona ghee and cream ghee.
The short version
A bilona is a wooden beater stood in a pot of curd and spun back and forth by a rope wound round its shaft, held upright by a stand or post. Churning shears the fat globules in the curd until their membranes tear and the fat clumps into grains that float to the top as makkhan. Sour curd churns more easily because acidity weakens the globule membrane, though curd that is too sour gives poorer butter. A hand churn applies little shear, so about a quarter of the fat stays in the buttermilk, and no study we found shows that hand churning beats an electric churner.
Sources
Further reading behind the figures above. Himdhara's own numbers — yields, batch results — come from our production records and the batch reports on the lab reports page.
- Halder K, Sahu JK, Naik SN, Mandal S, Bag SK (2021). Improvements in makkhan (traditional Indian cultured butter) production: a review. Journal of Food Science and Technology.
- Gregersen SB, Boesgaard LM, Neofytos DD, Andersen ME, Andersen U, Corredig M (2024). A simple and robust method for laboratory-scale preparation of butter. JDS Communications.
- Buldo P, Kirkensgaard JJK, Wiking L (2013). Crystallization mechanisms in cream during ripening and initial butter churning. Journal of Dairy Science.
- Design Innovation and Craft Resource Centre, CEPT University, and SADACC Trust (n.d.). Madani. Vernacular Furniture of India.
- Design Innovation and Craft Resource Centre, CEPT University, and SADACC Trust (n.d.). Rai. Vernacular Furniture of India.