Science of Butter: A Baker's Gem

 Butter origin dated back about 10,000 years ago to the time when our ancestors first began domesticating animals. The first reference to butter in our history was found on a 4500 year old limestone tablet illustrating how butter was made. It is generally believed the word butter originates from the boutyron, Greek for cow cheese, However it may have come from the language of cattle-herding Scythians. 

Butter is a dairy product containing up to 80% butterfat which is solid when chilled and at room temperature it is made by churning fresh or fermented cream or milk to separate the butterfat from the buttermilk. Butter consist butterfat, milk proteins and water.

Milk fat is comprised mostly of triglycerides, with small amounts of mono- and diglycerides, phospholipids, glycolipids, and lipo-proteins. The trigylcerides (98% of milkfat) are of diverse composition with respect to their component fatty acids, approximately 40% of which are unsaturated fat firmness varies with chain length, degree of unsaturation, and position of the fatty acids on the glycerol. Fat globules vary from 0.1 - 10 micron in diameter. The fat globule membrane is comprised of surface active materials: phospholipids and lipoproteins.

Fat globules typically aggregate in three ways:

• flocculation
• coalescence
• partial coalescence

Whipping and Churning

Many milk products foam easily. Skim milk foams copiously with the amount of foam being very dependent on the amount of residual fat - fat depresses foaming. The foaming agents are proteins, the amount of proteins in the foam are proportional to their contents in milk. Foaming is decreased in heat treated milk, possibly because denaturated whey proteins produce a more brittle protein layer at the interface. Fats tend to spread over the air-water interface and destabilize the foam; very small amounts of fats (including phospholipids) can destabilize a foam.

During the interaction of fat globules with air bubbles the globule may also be disrupted (this is the only way that fat globules can be disrupted without considerable energy input). Disruption of the fat globule by interaction between the fat globule and air bubbles is rare except in the case of newly formed air bubbles where the air-water interfacial layer is still thin. If part of the fat globule is solid, churning will result, hence the term "flotation churning" -from repeated rupturing of air bubbles and resulting coalescence of the adsorbed fat.

In spite of the above comments on the destabilization of foams by fat, milk fat is essential for the formation of stable whipped products which depend on the interaction between fat globules, air bubbles and plasma components (esp. proteins).

When cream is beaten air cells form more slowly partly because of higher viscosity and partly because the presence of fat causes immediate collapse of most of the larger bubbles. If most of the fat is liquid (high temperature) the fat globule membrane is not readily punctured and churning does not occur -at cold temperature where solid fat is present, churning (clumping) of the fat globule takes place. Clumps of globules begin to associate with air bubbles so that a network of air bubbles and fat clumps and globules form entrapping all the liquid and producing a stable foam. If beating continues the fat clumps increase in size until they become too large and too few to enclose the air cells, hence air bubbles coalesce, the foam begins to "leak" and ultimately butter and butter milk remain.

Kinds of Butter

Unsalted Butter -this is your best bet for cooking and baking. For many recipes, it is recommended that you bring the butter to room temperature first to incorporates with the other Ingredients. The exceptions is Pie Crust, for which cold butter is a must. If you want you can season salt into the butter according to your preferences when using it as a topping or spread.

Clarified Butter -when butter is melted and made clear by separating and discharging the milk solid and water, it makes a perfect dipping sauce for shellfish and other seafood and also in baking especially if you will make pancakes.

Cultured Butter -made from cultured cream, cultured butter has a rich complex flavor. It is ideal for baking because the lower moisture content produce flakier pastries and fluffier cakes.

European Style Butter -this old fashioned variation is made from cream that is churned more slowly  and for a longer time. It has a butter fat content at least 82% higher than standard butter. The increased amount of butterfat is beneficial for cooking and baking.

Whipped Butter -after it is churned, nitrogen gas is whipped  into butter to create this soft spreadable butter.

Functions of Butter in Baking

Flavor

the most obvious role in baking it adds a milky, oily and buttery rich taste .

To make baked goods tender 

butter in all fat in general create baked goods that are more tender. good example of making baguette and Brioche bread . Baguette falls into category of lean bread because of dough does not contain fat. Breads without fats is crusty outside and chewy on the inside. This is because there is no fat present to inhibit the formation of gluten strands. In contrast breads that contain fat in their dough  like brioche have a softer and more tender texture. Butter and all fats are solid at a room temperature. fall under the umbrella of baking term of shortening. This term comes from the way in which fat serves to shorten gluten strands. Without getting too depth into the science of it, when fats coats flour, it serves to slow down the process of gluten formation creating a more tender product.

To Leaven

In baking, when you think about how to make something rise, butter is not something comes to your mind, But butter can play an important role in leavening many baked goods. Puff pastry for example get its incredible rise solely from the butter that is layered through out the dough. Butter is not a pure fat, it does contain water. For this reason, when cold solid butter hits a hot oven, the water starts to evaporates and steams get trapped in the dough causes to rise.

Substitute of Butter in Baking

Lard -lard is the highest Pork Fat. it is snow white and has a very mild taste which is great for baking. It creates really tender baked goods. 

Margarine -the important thing to note about margarine is that the fat content are lower than butter. Butter is at least 80% fat and margarine is sometimes 35%. This means it has higher water content and can produced tougher baked goods. 

Vegetable Shortening -also has a higher melting point than butter which means that baked goods hold their shape a little better vs butter or lard. 

Sources: https://www.uoguelph.ca/foodscience/book-page/background-science-butter-churning

                https://bakerbettie.com/function-of-butter-in-baking/#Substituting_Butter_in_Baking

                http://www.butterinstitute.org/all-about-butter