The Science Behind Adding Milk to Tea and the Right Method

The Science Behind Adding Milk to Tea and the Right Method

Drinking tea is a fairly common occurrence in modern society since tea is one of our most popular drinks. It is also extremely interesting since multiple sources of tea leaves make it extremely versatile. Most tea drinkers have a preferred type that suits their palate or health needs, but countless more are just beginning to drink tea. 

As a result, some lack an understanding of how to properly steep tea from leaves or identify a quality blend. More importantly, newcomers to the world of tea might not have enough information about the impact of certain tea accessories. Specifically, the things we mix with our tea to modify the flavor or color to suit our preferences better. 

One staple of tea drinking is the addition of milk to a freshly steeped cup. Not everyone thinks to add milk to tea, primarily because it is not common in the United States. Nevertheless, millions of people choose to use milk as a flavor modifier in tea since some blends might not agree with their taste buds. 

On the surface, there is nothing to consider aside from preference when adding milk to your tea, but there might be more to it than we realize. Milk and tea are more complex than their status as beverages and interact with each other on a molecular level. Therefore, it would behoove anyone who intends to use tea to improve their health to understand the science behind milk and tea.

History of Milk and Tea

Tea is the 2nd most popular drink worldwide, second only to water and outranking coffee significantly. While tea is widespread now, it was originally restricted to East Asia and primarily consumed by the Chinese. The Chinese consumed tea before refining it into a beverage and were directly responsible for its spread to the wider world. 

While early Chinese civilization chewed on raw Camellia sinensis leaves to take advantage of the nutrients, a process to convert it to a liquid was eventually discovered. Evidence suggests that tea drinking was introduced by southwestern Chinese culture; however, there is a lot of speculation surrounding when it was first developed. Even when tea drinking was invented, tea was used to create other edible products for creative tea consumption. 

Different Chinese dynasties created alternate methods for steeping tea, such as the Tang dynasty's method of steaming the leaves, pounding them, and shaping them into small cakes.

Tea's origins in China eventually spread across Asia, becoming a cultural and religious tool in Japanese society and Buddhism. Tea began spreading in earnest in the 16th century when the Dutch East India Company transported a shipment from Japan to Europe.

The Dutch were responsible for introducing tea to Germany, France, and eventually America (while under British control). While the spread of tea was impressive, one of the most important countries to get ahold of tea was the British, who generated an entire subculture around it. The British love of tea was not as sacred as that of Japan's (who performed small ceremonies when steeping tea), but Britain remains one of the hubs of tea culture.

Milk and Tea

It is believed that the British first began using milk to alter the tea's base flavor. The British used milk to mellow the flavor and avoid the bitterness in tea or coffee. The tannins found in tea are partially responsible for the bitter flavor, but adding things like milk or sugar allowed drinkers to reduce the bitterness and make the drink easier to consume.

While flavor modulation is important, there are questions about how tea and milk interact with each other and affect their structure. More accurately, people want to know if adding milk to their tea reduces the latter's nutritional value.

How Does Milk Alter Flavor?

The tannins in pure tea are astringent, which is why there is always bitterness in a cup of any tea variety you drink. Additionally, few tea plants have natural sugar content, which allows the bitter flavor to take a more direct role in the overall flavor profile. Generally, the bitterness is secondary to the other flavors inherent in the plant (such as some tea varieties having a natural citric zest). 

Astringents play a significant role in several products and compounds, primarily as a tool in skincare. Despite their role in lotions and cosmetics, they are not typically added to anything and are native to the plants used as the core ingredient. Tea leaves are no exception and contain tannins that are powerful astringents called catechins. The simple solution would be to try and breed the tannins out or learn to filter them from the final product. 

Unfortunately, the same compounds responsible for the bitterness are also the source of tea's nutritional and health benefits. The most powerful catechin in a cup of tea is called epigallocatechin gallate (EGCG) and is the main source of tea's benefits.

Therefore, removing the EGCG would eliminate a large chunk of bitterness and the lion's share of the drink's benefits. The inability to take full advantage of tea without catechins is why altering the flavor has become so important to modern consumers.

A Cup of Tea

While sugar is generally an effective tool against bitterness, milk has a surprising impact on the tannins in a cup of tea. There is research suggesting that milk inhibits the astringency of tea's tannins and reduces the bitterness. In fact, the reduced astringency actively improves the tea's flavor and prevents dryness in the mouth after taking a sip.

The ability to alter the bitterness of a cup of tea was the main focus of adding milk, but there is almost always a catch. While milk reduces the drink's bitterness, it changes the tea's basic structure and alters how it functions. These changes are not all beneficial and could reduce the tea's value depending on how much milk you add. The question is: What does the milk change that affects the tea's nutritional value?

Does Adding Milk Affect Tea's Nutrition?

Adding any substance to another is going to generate a chemical reaction, even if that reaction can be classified as "minor." While most people associate chemical reactions with the stuff you see in a chemistry lab, the process can occur with common household substances like tea and milk. Tea and milk have different molecular structures that must be mixed to become a single substance. 

Some compounds cannot mix because their molecular and chemical structures are too different, but milk can mix with tea completely. These chemical changes are significant enough that it begs the question of whether milk's molecules eliminate the beneficial tea molecules. As much as we would love to give a definitive answer, there does not seem to be one since most research on the topic is mixed. 

Some research indicates that milk interferes with the health benefits of tea, while others indicate the opposite. Unfortunately, there does seem to be a change in tea's structure that is not ideal for taking advantage of its benefits.

Adding Milk to a Cup of Tea

In 2007, a study published in the European Heart Journal claimed that previous studies had not found a straight answer as to whether adding milk lowers tea's health properties. Despite that, the same study discovered that adding 10% milk to a cup of tea significantly lowered the concentrations of several catechins (though the caffeine levels remained intact). 

Similarly, a 2009 study from Oxford corroborated this result and indicated that adding milk to tea lowers the catechin levels in tea. Considering that catechins are the driving force behind tea's health benefits, these results are not what you might call "promising." When you consider one of the more practical studies conducted on milk tea, things get more upsetting.

Black tea, one of the varieties harvested from C. sinensis, is renowned for its ability to improve blood flow and heart function. One study assessed this trait by taking 16 women and dividing them into groups. One group was given 2 cups of plain black tea, and another was given black tea mixed with skim milk. 

When the study concluded, it was determined that the subjects given plain black tea enjoyed all the benefits of black tea concerning heart health. Meanwhile, the subjects given milk tea showed no cardiovascular improvements and retained the same heart function as before the study. These researchers hypothesized that a protein called casein, found in milk, can bind to the flavonoids in tea and inhibit their function.

Therefore, it can safely be said that adding milk to tea can inhibit certain aspects of its health benefits. Overall, tea mixed with milk is still very healthy and might even provide some unique benefits since milk is good for us on its own merit. Unfortunately, the advantages afforded by pure tea might be diluted if you decide to add milk. Fortunately, reducing milk's impact on your tea might be possible if you know how to add it properly.

What is the "Right Way" to Add Milk to Tea?

There is usually a "right way" to do things if you want to succeed at a specific task, but sometimes the "right way" is more abstract than we might like. Insofar as adding milk to tea is concerned, abstract is putting it mildly. Ultimately, there is no official "right way" to add milk to tea since two liquids without volatile characteristics can usually mix together without backfiring. 

The main question is whether there is a correct order, such as whether you should add the milk to the tea or vice versa. This has been a slightly divisive topic among British citizens, and even famed novelist George Orwell added his opinion that the tea should be poured before the milk. That said, no scientific evidence proves that adding tea before milk or milk before tea impacts the mixture.

Milk With a Cup of Tea

This particular debate is a matter of preference and will not alter the characteristics of the tea beyond what is normal when adding milk. That said, there is a list of "golden rules" concerning mixing tea and milk. These rules are:

  • The Amount: The general consensus among British citizens is that 5 milliliters of milk is the ideal amount for tea. Adding more than that could mask the tea's natural flavors, while less could fail to mask the bitterness. Unfortunately, nothing suggests that the amount of milk changes its impact on the tea's molecular structure.
  • The Temperature: Adding cold milk to hot tea can help reduce the temperature so you do not burn your mouth. That said, steeping your tea at the proper temperature is crucial to preserving your tannins since high temperatures could burn your tannins away.
  • The Type: It is commonly believed that black teas are best suited to milk since the more powerful flavor will not be drowned out by the milk. Furthermore, the catechins in black tea are more concentrated than in green tea, so they might be less affected by milk.

Ultimately, the addition of milk to tea seems to have no scientific "right way," but there is a cultural one. The simple truth is that more research is needed to determine whether there is some magic method to adding milk to tea without reducing its effects. If you are willing to drink tea without milk, you can find several blends that are naturally less bitter and still wonderful for your health. The biggest challenge, as always, is finding a blend that meets those criteria and does not need to be adulterated with milk.

Finding the Right Blend

We at Teami have a longstanding love for tea that has driven us to create our own blends using natural and exotic plants. We have an entire catalog of tea blends that use leaves from the standard C. sinensis and several other plants known for producing teas. Our blends are designed to maximize the health and nutritional benefits of tea leaves.

Teami Tea Blends

While we do not have milk to sell, you might find that our blends do not need as much flavor adjustment since we add other natural substances to keep the flavors balanced. We encourage you to visit our website and peruse our full catalog of tea. After all, finding the right blend is a Teami effort.

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