Engineering the Perfect Chai
“How did Chai Hous develop such a delicious chai?” you might be wondering. As a Chemical Engineer, I am trained to use the scientific method to develop experiments and analyze data in the process of designing and optimizing a product. In this case, that product is a better cup of chai tea. Through my experiments to create the perfect blend of chai spices, I found numerous surprising results. Some results supported a traditional blend of chai spices while others clashed with tradition.
First, a traditional chai blend can contain black tea, ginger, cinnamon, cardamom, cardamom seeds, star anise, anise seeds, pepper, cloves, coriander seeds, nutmeg, fennel, and tulsi basil. Ginger also comes in dried and crystalized forms. With each spice and herb imparting its own competing flavor to the mix, this gives us 17 independent variables including steeping time, sugar, and milk. Other chai blends introduce additional flavors such as peppermint, each adding an additional variable to consider.
With this in mind, our first step was to eliminate unnecessary flavors. In testing dozens of chai mixes, all of the Chai House taste testers found they preferred or strongly preferred chai without any cloves and without tulsi basil. Other flavors were found to have negligible impacts on flavor. Finally, we were left with a more manageable list of 8 initial variables: 5 of the traditional ingredients, plus steep time, sweetener, and milk, totaling less than half of our original list.
Our next test (before accounting for what type of sweetener we were using) focused on how sweet verses how spicy a spicy ginger chai should be. While this is always a matter of personal preference, we found some interesting results that might help you when sweetening your drink. It turns out that there is a "sweet spot," so to speak, a narrow band of just right between not sweet enough and too sweet. This effect can be seen in the "S" shape of the sweet flavor line in Figure 1. This experiment was also interesting as it revealed that ginger without any added sweetener has no ginger flavor, only spiciness. Sweetness is required brings out the ginger flavor. All our tests after this point used cane sugar as a sweetener as honey proved to be too inconsistent in flavor, adding subtleties to the chai tea that interfered with taste testing.
Figure 1: Relative flavor strengths of ginger with increasing concentrations of sweetener.
NOTE: due to the bittering effects of tea and cardamom, I find that my personal sweet spot for Chai Hous’ chai is around 1.5 – 2 Tbsp of sweetener per cup of H2O. As seen in Figure 1, less sweetener will result in a spicier chai while more will give a sweeter flavor.
Next, was finding the proper balance between ginger and cinnamon, our two main ingredients. Too much in one direction or the other and the chai began tasting like cinnamon tea or ginger tea without any other flavors. While cinnamon tea and ginger tea are both tasty treats, they fail to present all of the other undertones introduced by the other chai spices. In fact, during this phase of testing, Chai Hous taste testers all liked tea with ginger and cinnamon only, but all ranked ginger-cinnamon tea the lowest compared to other chai teas, showing that the flavors from the other chai spices do play a critical role in giving chai its flavor. A 2:1 ratio by volume of ginger to cinnamon was found to be a favorite among taste testers giving a strong ginger taste but still with hints of cinnamon. Little more ginger than this results in an overwhelming ginger flavor without any cinnamon while a 1:1 ratio tasted like cinnamon tea without any ginger.
After finding a ratio where ginger and cinnamon harmonize instead of clash, we began testing with different combinations of other chai spices added in. Cardamom immediately proved to be a problem. Most tea blogs recommend steeping tea for about 5 minutes, however, the dried spices in chai like ginger, cinnamon, and cardamom require longer to infuse their flavors into the brew. The longer tea steeps, the more bitter the drink becomes, until at around the 9 to 10 minute mark, tea leaves flood the drink with tannins (the same chemicals that add a bitter flavor to wine). Throughout the brewing, Cardamom adds its own bitterness to the mix, synergizing with the tea’s bitterness. Altogether, when brewing chai, there is a race between the spice flavors against a steadily increasing bitterness. This competition between flavors can be seen in Figure 2a and 2b where the blue line represents bitter flavor increases with time while the relative strength of other flavors could not keep up.
Figure 2a: Relative flavor strength of chai components from samples taken each minute.
Figure 2b: Relative flavor strength of chai components by percentage
This test was repeated multiple times with different volumes of cardamom included in the spice mix. The data from these tests confirmed that cardamom was a major contributor to a bitter flavor (all graphs available in Appendix A). After testing several different volumes of cardamom, an “ultra-light” volume of cardamom was selected for Chai Hous blends to prevent runaway bitterness as seen in Figure 3. Additionally, these tests consistently showed a spike in relative strength of ginger flavor at the 7-minute mark before runaway bitterness took effect. Later timing tests would confirm that a 7-minute steep time was preferred by all Chai Hous taste testers, and that the flavor is about the same within 30 seconds before or after the 7-minute mark.
Figure 3: Relative strength of cardamom flavor over time at different concentrations.
Once ginger, cinnamon, and bitterness from tea and cardamom were balanced, the rest of the chai spices could be tested at varying concentrations. Each test was one step closer to optimizing the perfect chai. The greatest difficulty of this step of testing, with so many different spices, was accounting for how a change in concentration of a single spice could lead to distasteful synergies of flavors requiring adjustments to other variables. These iterative tests lead to the elimination of some spices and the addition of other traditional ingredients, until eventually, the perfect blend of spices, each at their respective proportion, was developed.
An additional note about steeping tea in a pan verses teapot. Chai Hous recommends using a stovetop pan to steep rather than a teapot. The pan allows the chai spices to be stirred around, increasing the rate of extraction of spices from their solid bodies and diffusion into the tea, while a teapot holds the tea together limiting the speed of extraction. Chai Hous tests have found tea pot steeped chai to bee weak and watery at the 7 minute mark. If you must use a teapot, we recommend increasing steeping time to 9 minutes for stronger chai flavors, but keep in mind, at the 9 minute mark, the runaway bitterness effect will have begun, as seen in Figure 3. However you choose to enjoy, we know you’ll love our chai.
So, treat yourself to a better cup of chai with the world’s first chai tea designed using science!
Appendix A: Graphs From Chai Hous Taste Tests
Figure 1: Relative flavor strengths of ginger with increasing concentrations of sweetener.
Figure 2a: Relative flavor strength of chai components from samples taken each minute with heavy cardamom.
Figure 2b: Relative flavor strength of chai components by percentage with heavy cardamom.
Figure 2c: Relative flavor strength of chai components from samples taken each minute with medium cardamom.
Figure 2d: Relative flavor strength of chai components by percentage with medium cardamom.
Figure 2e: Relative flavor strength of chai components from samples taken each minute with light cardamom.
Figure 2f: Relative flavor strength of chai components by percentage with light cardamom.
Figure 2g: Relative flavor strength of chai components from samples taken each minute with ultra light cardamom.
Figure 2f: Relative flavor strength of chai components by percentage with ultra light cardamom.
Figure 3: Relative strength of cardamom flavor over time at different concentrations.
About the Author
As a chemical engineer, Spencer Lane, Chai Hous’ Chief Brewing Officer, is fascinated with the chemistry of health. Researching what causes sickness led him to understand how nutrition plays a critical role in every day health. Based on his research on chai spices, he feels he has discovered the alchemical elixir of life, or, as a sci fi fan, the Spice. “The most precious substance in the universe is the spice mélange… The spice extends life.” – Frank Herbert, Dune