With its eye-catching orange hue and bold flavor, Thai iced tea (ชาไทย)— usually called cha yen (ชาเย็น or iced tea) or sometimes cha nom yen (ชานมเย็น or iced milk tea)—is a staple of daily life in Thailand. Walk down any busy street, and you’re bound to find a cart or hole in the wall where vendors take black powder from a banged up tin and churn out glass after glass of the terracotta-hued beverage. It’s an anytime, anywhere kind of drink: Locals sip it in the morning with pa tong koh (the Thai equivalent of Chinese youtiao), have it as a palate cleanser between bites of fiery pad kra pao, and use it to cool down after steaming bowls of boat noodles. My favorite way to enjoy it, though, is on its own. On a hot day, a sip of the cold, sweet beverage feels like a luxury. 

A Brief History of Thai Iced Tea

Thai iced tea is simply strong black tea—usually Ceylon, Assam, or a locally grown assamica varietal—mixed with milk and sugar and served over ice. There’s no single approach to making the drink; the type of dairy and sweeteners used, and how much, can vary greatly from vendor to vendor. While sweetened condensed milk isn’t mandatory, it is a common enough addition that many Thais, myself included, consider it an essential ingredient for cha yen. 

Though camellia sinensis assamica is native to the region, the leaves of the indigenous plant were traditionally eaten (usually in the form of fermented tea leaves called Miang), rather than brewed. Tea drinking culture likely arrived some time during the Sukhothai period between the 13th and 16th century through trade with China. One of the first written records of tea culture in Siam can be traced to a 1691entry in French diplomat Simon de la Loubère’s travelog Du Royaume de Siam, where de la Loubère discussed the practice Ayutthaya’s elites had of serving hot tea in the Chinese style to guests in their homes. 

Although the Siamese continued to serve tea in formal settings such as government and temple functions, the beverage’s consumption and popularity remained limited until the 20th century, when the arrival of two crucial products—sweetened condensed milk and ice—laid the groundwork for the advent of cha yen.  

In 1893, Nestlé introduced its Milkmaid brand of sweetened condensed milk to Siam, kicking off a national love affair with the dairy product that continues to this day. Its shelf-stable nature and concentrated flavor made sweetened condensed milk a staple at coffee and tea shops, as the ingredient offered customers a convenient way to temper their bitter brews with something sweet and creamy.  By the 1930s, the product had become so popular that the government made efforts to increase domestic production. 

In 1903, businessman Lert Sreshthaputra, commonly called Nai Lert, founded Bangkok’s first commercial ice manufacturer, a move that made ice and cold treats more accessible to the masses. (Prior to Nai Lert’s ice works, ice was imported by boat from Singapore, so it was an expensive good reserved for the wealthy.) By the 1920s, coffee houses serving hot and iced drinks had gained popularity across the Kingdom.

Why Is Thai Iced Tea So Orange?

While the Ceylon, Assam, and locally-grown assamica leaves typically used for cha yen do yield a reddish-brown brew, the iconic orange color we associate with Thai tea comes, more often than not, from food coloring. Anticlimactic, I know.

No one knows exactly how and when Thai tea picked up its fake tan, but speculation abounds. One theory posits that crafty vendors in the late 19th to early 20th century started adding fillers like safflower and tamarind to lower quality tea leaves in order to mimic the deep mahogany hue of pricier imported Ceylon tea. Another theory credits resourceful Siamese servants who, horrified that their English employers were throwing away perfectly good tea leaves after just one brew, started doctoring spent tea leaves with coloring in order to make second and third brews more visually appealing. Others suspect that coffee houses started amplifying the reddish hue of their tea to help differentiate between coffee and tea, since the two drinks look similar once sweetened condensed milk is added.

3 Tips for Making the Best Thai Iced Tea

1. Use the right tea. You can, of course, make perfectly good cha yen with good quality Assam or Ceylon tea (see Swetha Sivakumar’s chai recipe for an in-depth primer on tea leaves), but that approach is a little like serving a fancy tomato relish with fries when store-bought ketchup is probably better suited for the job. 

Instead, for cha yen reminiscent of a Bangkok beverage cart auntie’s, I opt for a ready-made Thai tea blend, which typically contains tea leaves, vanilla extract and other flavorings (while labels are typically obtuse, my educated guess is that these include cinnamon and star anise, among other ingredients). And of course, these blends usually include colorants for that perfect burnt sienna hue. I prefer the assertive flavor and deep color of ChaTraMue’s “Extra Gold” blend, but feel free to use one you like or can find more readily. I recommend skipping the three-in-one or instant mixes, since these already include creamer and/or dried milk powder.

2. Stir and strain well. Because of its finer particles, Thai tea powder has a tendency to clump up in water. To ensure the tea is adequately and evenly exposed to hot water, it’s essential to agitate the tea by stirring it. This allows for the release of more water soluble polyphenols called flavonoids, producing a stronger, more flavorful brew—and is why many vendors pour tea back and forth through a cloth strainer several times before removing the solids. At home, I opt for a simpler method: thoroughly stirring the tea right after adding water and again right before straining. This second stir also helps move more tea powder into the strainer.

Since most Thai tea mixes are finely ground, a cloth tea strainer like the ones street vendors use helps filter out tea particles that are too small for regular mesh strainers. If you can’t find one, use cheesecloth, a clean, flat dish towel (one you don’t mind staining orange), or a coffee filter fitted over a mesh strainer instead.

3. Opt for Canned Milk. What dairy yields the creamiest, dreamiest Thai iced tea? Recipes run the gamut, calling for ingredients ranging from artificial creamer to half and half. After rounds of testing, my favorite is ultimately a one to one combination of sweetened condensed milk and evaporated milk. 

Invented in the 1850s by American newspaperman Gail Borden as a way to preserve cow’s milk, sweetened condensed milk has, over the course of nearly two centuries, become an ubiquitous ingredient in Southeast Asia. Made by cooking down milk and sugar, sweetened condensed milk gives Thai iced tea its satisfying sweetness. Additionally, it gives the tea base a more syrupy texture, making it less watery when ice is added. Opt for the canned version, or try making your own using former Serious Eats editor Stella Parks’ sweetened condensed milk recipe. 

Similar to its sweetened sibling, evaporated milk (sometimes called unsweetened condensed milk) is made by cooking down milk to remove 60% of its water content—just without added sugar. Because of its long shelf life, it is the most convenient way to store and transport fluid milk in Thailand’s hot climate. Evaporated milk’s low water content and concentrated flavor gives the tea more body without making it too cloyingly sweet. Its slightly caramelized flavor also adds another layer of complexity.

Thai iced tea is an incredibly nostalgic beverage for me. Every sip conjures up childhood memories of hot afternoons spent outdoors with a plastic bag of cha yen—adorned with a neon staw and slick with condensation—in hand. Nowadays, Thai iced tea can easily be purchased in Thai restaurants across the country. But for a truly delicious Thai iced tea that’s flavorful and full-bodied, I’d much rather make it myself…and I think you will, too.