Butter Versus Margarine

Butter and margarine appear to do the same job in a kitchen. But they diverge from production through to their nutritional profiles.

How is each produced?

Butter is made from the fat phase of milk.

Cream is separated from the milk and then churned.

During churning the fat globules coalesce and separate from the water phase.

That is called phase inversion; an oil-in-water emulsion becomes a water-in-oil emulsion.

The product is washed, worked and shaped.

Milk is the only raw material; nothing else is added.

Margarine is made from vegetable oils.

Liquid vegetable oils are processed to make them solid.

That was formerly done by hydrogenation; today interesterification and fat blending are largely used.

Water, salt, emulsifiers, vitamins and flavourings are added.

The result resembles butter but carries a different fat profile.

How do the fatty acid profiles differ?

That is the most fundamental difference between the two.

Around 63 percent of butter's fatty acids are saturated.

Monounsaturated make up 26 percent and polyunsaturated 4.

It also contains short-chain fatty acids; butyric acid belongs to that group and gives butter its characteristic aroma.

It contains cholesterol: around 215 milligrams per hundred grams.

Margarine's profile varies with the vegetable oils used.

Sunflower, canola, palm and coconut oils all appear.

Saturated fat runs 20 to 45 percent; higher in palm-led products.

Polyunsaturated fat is generally markedly higher than in butter.

It contains no cholesterol, being plant-based.

Where does the trans fat question stand?

This is what margarine is criticised for most, and the situation has changed.

The old production method used partial hydrogenation.

That process solidified liquid oil while producing trans fatty acids.

The adverse effect of trans fats on heart health was established.

Regulations tightened as a result; industrial trans fat is limited or banned in many countries.

Most margarine produced today carries trans fat below 1 percent.

The production method changed; interesterification produces no trans fat.

The claim that margarine contains trans fat is therefore out of date.

But the label still deserves checking; where "partially hydrogenated" appears, the product was made by the old method.

Butter naturally contains a small amount of trans fat too; that is ruminant-derived and assessed differently from industrial trans fat.

What does melting behaviour change?

This is the most practical difference in the kitchen.

Butter melts at 32 to 35 degrees, just below body temperature.

That gives a fast, smooth melt in the mouth.

The aroma compounds are released by that melt.

Margarine generally melts at 35 to 40 degrees.

That means a slower melt and, in some products, a waxy sensation.

The melting range differs too; butter melts gradually across a wide range while margarine works within a narrower one.

That difference becomes important in dough.

Butter is hard from the fridge and soft at room temperature; that transition is exploited in laminated doughs.

Margarine holds its consistency across a wider temperature range, which is an advantage in some applications.

What functions do they serve in dough?

Both perform the same basic job as fat: blocking gluten.

But the details differ.

Butter is the traditional choice in laminated doughs; its melting behaviour suits layer formation.

Puff pastry and croissants belong there.

But butter is a difficult material to work with; it demands temperature control.

Pastry margarines are made specifically for that job; their plasticity is high and they work across a wide temperature range.

Both can be used in biscuits and cakes.

Butter adds aroma and gives a crisper texture.

Margarine gives a softer texture and the product stays soft longer.

Butter is preferred in creams, where aroma is decisive.

Neither suits frying; their smoke points are low.

How pronounced is the difference in aroma?

Butter's aroma comes from diacetyl and short-chain fatty acids.

Those compounds occur naturally in milk.

In cultured butter the aroma is more intense; fermentation produces additional compounds.

Aroma is added to margarine afterwards, generally using diacetyl or nature-identical compounds.

That aroma can read close to butter in cold applications.

But the gap widens in cooking.

When butter heats, its milk proteins brown and new aroma compounds form.

That is the source of the browned-butter aroma.

Margarine contains little or no milk protein; that reaction does not occur.

The difference is clearly felt in baked goods.

Which fat should be chosen when?

The decision rests on three criteria.

The first is purpose. Where aroma leads, butter; where cost and ease of handling lead, margarine.

The second is product type. Pastry margarine offers a technical advantage in laminated doughs; butter offers an aroma advantage in biscuits and cakes.

The third is dietary preference. For anyone limiting saturated fat, a margarine led by unsaturated oils suits; but the saturated fat figure on the label deserves checking.

In palm-led margarines the saturated fat can approach that of butter.

For anyone eating a vegan diet margarine is the only option, though a product containing no milk fat must be chosen.

Mixed use is common too; margarine for cost and butter for aroma, used together.

That is the commonest approach in businesses.

How do the two behave in baking?

Butter and margarine behave differently in an oven.

Butter contains 16 to 18 percent water.

That water produces steam in a dough and contributes to lamination.

The water in margarine varies by variety, reaching 20 percent in some products.

Their melting points differ too; butter melts at 32 to 35 degrees and margarine generally at a higher temperature.

That makes doughs with margarine spread later.

The difference is visible in biscuit recipes; biscuits made with margarine come out thicker and less spread.

Butter is markedly richer in taste; its milk solids carry aroma.

Margarine gives a neutral taste and lets other aromas come forward.

In laminated doughs a specialised pastry margarine performs better than butter, since its wider plastic range tolerates a warm kitchen; in a domestic kitchen that can matter more than the difference in flavour.