Category Archives: General Tea Background

Tea Geek: Understanding CO2 Decaffeination

Leave a reply
Caffeine Chemical Makeup - Decaffeination Doesn't Remove It All!

Chemical Makeup of Caffeine

Is decaffeinated tea something you drink regularly? Ever wonder how tea is decaffeinated? The process for decaffeinating tea is much like washing dishes in a sink, though with a few extra steps so you actually end up with clean dishes (tea) rather than dishes that have sat in swirling, dirty water (albeit with a bit of soap for good measure).

As you may know, there are several methods by which tea (and coffee for that matter) are decaffeinated. While coffee has the “swiss water method” in addition, tea is predominantly decaffeinated using one of two methods, the ethyl acetate or the CO2 method. While the ethyl acetate method is referred to as natural decaffeination, the chemical, an organic solvent technically, appears in many products including nail polish remover and cigarettes. Doesn’t exactly leave a great taste in your mouth to learn that, does it? This is one of the reasons why high quality tea companies like Dominion Tea, steer clear of “natural decaffeination”.

Given that we humans generally exhale carbon dioxide (CO2), its use in decaffeination is something that consumers find much more appealing than the alternatives. You may have heard the CO2 process referred to as a CO2 bath or as using supercritical CO2 but what is this really?

Tea Decaffeination with Supercritical CO2

Diagram of phases of CO2 - supercritical fluid is used in decaffeination.

Carbon Dioxide at various temperatures and pressures. (Public Domain)

In a nutshell supercritical CO2 is carbon dioxide held under very high pressure in a state where this gas actually becomes somewhat liquid (almost a thick fog). Remove the pressure and the liquid turns into a gas and evaporates. Nice, clean and simple. However, you wouldn’t to wash dishes in a sink and simply pull the plug, leaving the detergent and all the leftover food and grease to sit and dry back onto the dishes would you? So clearly this process has a couple extra steps…

The process for decaffeinating tea with supercritical CO2 requires some mechanism to separate the caffeine from the tea so it doesn’t remain after the CO2 is removed. There are several methods for doing this, all starting with tea in a closed container of CO2 at 3,700 to 5,000 pounds of pressure per square inch! After “bathing” the tea in supercritical CO2, various mechanisms are used to move the caffeine away from the tea before pressure is removed and the leftover CO2 evaporates.

Incidentally, the leftover caffeine isn’t pitched. Instead, its sold to other companies which use it in soda, sports products, and even some foods.

Challenges with Supercritical CO2 Decaffeination

There are several challenges with this process of producing decaf tea, some technical, and some with the resulting product. The removal of caffeine tends also to remove other flavor compounds since carbon dioxide can’t perfectly target only caffeine. So the various methods seek to try to limit removal of other “good” compounds or add them back. Each of these processes add time and cost to the end product. Some are more energy, time, and labor intensive than others. However, all methods result in a cost per pound of decaf tea that is significantly higher than that of fully caffeinated tea.

Technical challenges aside, from a consumer perspective the decaf tea costs more to purchase, may have a flat or at least less flavor, and still has a low level of caffeine in it. Since it still has caffeine, even drinking decaf tea in the afternoon or evenings can leave some with jitters or trouble falling asleep.

Since the labor and cost of decaf tea is high, and comes with less flavor, companies typically only decaffeinate a select number of teas. In the case of Dominion Tea, this is why you won’t find a lot of decaffeinated tea options. We do have a couple (Earl Grey Decaf and Summer Peach Decaf), however we prefer to focus on great tasting fully caffeine free options with a rooibos or honeybush base or select herbal teas.

 

Sources:

US Patent US4976979 A – Process for the decaffeination of tea, by Hubertus Klima, Erwin Schutz, Heinz-Rudiger Vollbrecht, https://google.com/patents/US4976979

US Patent US5288511 A – Supercritical carbon dioxide decaffeination of acidified coffee, by Peter T. Kazlas, Richard D. Novak, Raymond J. Robey, https://google.com/patents/US5288511

Water Quality for a Great Tea Experience

Leave a reply
Water droplets.

Do you have great water quality for your tea? Are you sure?

Are you sacrificing a great cup of tea because your water leaves a little something to be desired? Water is the single biggest ingredient in your cup of tea so making sure you have great water quality is a great idea; especially if you have a well!

What is Water Quality?

Well the answer, like that of what is quality tea is, it depends. Water quality can be subjective and depends on the application. It’s really probably better to think in terms of fitness for use. Quality water for swimming, showering, and washing clothes is a very different discussion from the water quality desired for tea.

Its important to start off with a baseline. A large part of what we are trying to do when we make a cup of tea is steep leaves in water in order to extract the favor (and usually caffeine as well) from the leaves. The leaves contain both water soluble and water in-soluble compounds that can impact flavor.  And some of these compounds are more soluble than others at a given temperature. We are looking to extract desirable flavor compounds while minimizing the tannins which result in bitterness.

So for tea we are looking for the ideal water to extract the right amount of flavor.

All We Want is Fresh Clear Water, Right?

Since we are looking for the best water to extract the right balance of flavor what does this look like?  In short, fresh clean water, without off odors, and which has some minerals but isn’t too hard. Sounds easy right?  Here are a few things you will want to know.

  • Tap water is not the same across the country.  Some areas have naturally harder (or softer) water than others. Hardness being a measure of dissolved minerals. The ideal hardness for tea is between 50 and 100 parts per million.
  • Calcium in water creates scale which damages electric tea kettles and increases the energy required to boil water.
  • Public water supplies may have added chlorine and fluoride, may not be as soft as desired, and after travelling through a network of pipes, may not be as clean as you think.
  • Private (aka well) water may be all over the map. It depends where you live, how deep a well you have, what the local geology looks like, and more. While well water is tested for new wells this is minimal testing, primarily for coliform.  It’s not necessarily for radon, pesticides, hardness,  or other things which impact water quality.
  • We do not want distilled water or reverse osmosis water.  The former leaves behind all minerals but not volatile organic compounds (for example benzene or other fuel-related components).  The latter provides pure water with no minerals; flat, boring, and providing an equally boring cup of tea.

Getting Great Water Quality for Tea

First and foremost get your water tested.  If you are on public water you can get a good baseline from the annual water quality report put out by your jurisdiction. However, this will only have basic information in it and won’t account for what happens on the journey from source to destination. It’s a great idea to get your personal water supply tested.  If you are on a well this is really a must as water quality changes over time due to groundwater changes or due to damage to your well head or casing. As a homeowner you will only know the full details of your water by testing yourself. The CDC offers some thoughts on testing.

After testing, consider available solutions to address your water situation. This may be a basic sediment filter, a carbon filter to remove odors and other organics, softening through sodium (salt) ion exchange, and/or scale inhibitors.  Its important to realize that there generally is not a one-sized fits all solution, you may use a combination of methods, and you may want to consider cost and options for treating all your water or only drinking water.

One more note on water quality. While we stated that its different from place to place there are exceptions for large nationwide coffee/tea chains and similar establishments. These businesses are looking for an exact flavor experience every time regardless of which shop you visit. These establishments actually use reverse osmosis to remove everything from the water. Then they use a pre-formulated solution to add back the exact mineral content for exactly the same water, everywhere!

Finally, A Note on Descaling Your Electric Kettle

Pamukkale Travertines of Turkey. Water quality for tea is a measure of disolved solids. In this case lots of calcium formed the travertines.

Extreme Example of Calcium (Scale) Buildup at the Pamukkale Travertines in Tukey. Photo by flickr user SaraYeomans (CC BY 2.0)

We find it amusing that the answer to scale or calcium buildup in your kettle is to purchase special descaling chemicals. However, regular descaling, as if it occurs at the same rate everywhere, is exactly what many electric kettle manuals even claim you should do! Scale, or calcium buildup depends on water hardness which, as we’ve seen, varies dramatically across the country as well as between well and municipal water. So descaling monthly is a bit inappropriate for many consumers. Regardless, you can use white vinegar to remove scale, so why buy something else? More importantly, if you are looking to enjoy your tea and you have excessive mineral buildup in your kettle then you have a bigger problem: hard water. By now you know that the first step is to have your water tested so you know what you are dealing with, can treat it appropriately to have great water quality, and ultimately have a great tea experience.

 

Tea Storage for Optimal Freshness and Shelf Life

Leave a reply

Correct tea storage provides the longest shelf life possible. This is important for all tea drinkers as your want your last cup to be as good as your first. So to get this correct, we need some basic understanding of how tea interacts with the environment and what the expected shelf life of tea really is. Keep in mind, if stored correctly the expected shelf life can go out much further than what is indicated below. The taste of tea, however, will change on you from when you first bought.

Then we can figure out where and how to store tea. Below is a chart that lays out the different types of teas and how long they are expected to keep their original flavor for if given the optimal treatment in the trip to market and then onto your shelves at home.

Tea Type Expected Shelf Live Tea Storage Comments
Black 24-36 months Since this tea is generally dried longer, it will last longer under the right conditions.
Oolong 12-36 months The darker the oolong the longer the shelf life.
Green and Yellow 6-24 months The British Tea Council advises to drink the green teas before 6 months as the anti-oxidants will break down over time. If taste is more your concern, you are fine going out 12 months for most.
White 6-12 months Since white tea is made from younger leaves with the least amount of manufacturing, so this is not a tea to keep long.
Blended with Flavoring 6-36 months Extracts have long shelf lives, so it is the tea base that will dictate this shelf life
Blended with spices, flowers, herbs 6-12 months Here the spices more than the tea dictate the shelf life. Cinnamon, mint, and cloves will start to lose their punch after six months. Most flowers add no flavor and will stay as long as the tea.
Blended with Nuts 6 months Nuts go bad quickly, that is why you often don’t find them in tea. If a tea is nut flavored, it is generally through extracts.
Puerh Generally the older the better, some of the best on the market are 20-30 years old, unlike the other tea, this one needs air to improve its flavor Puerh needs air, so if you buy it store it somewhere other than the kitchen to allow for proper air circulation without it picking up the odors from your cooking.

Your favorite antique tea tin may not provide the best tea storage solution.

Your Favorite Tea Storage Tin May Impair Freshness

Tea Storage Conditions

Tea is hygroscopic, which means it will absorb moisture and odor from the air. So it needs an air-tight container, kept away from spices, garlic, onions, and anything else that has strong odors in the kitchen. Tea should also be kept away from heat. Generally in a kitchen, when food is heated it releases steam and the tea will absorb all of it. So never store your tea near or above your oven, cook top, dishwasher, or microwave. By doing that, you are just asking to have your morning tea taste like last night’s dinner. Finally, tea is also light sensitive. Remember, the sun is used to whither the freshly plucked tea leaves. So more sun on the dried tea leaves, will just break them down faster. So its best to stay away from clear containers.

Best Tea Storage Options

Sencha Green Tea in Resealable Pouch for Optimal Tea Storage

Japanese Sencha in an Air-Tight Tea Storage Pouch to Optimize Freshness

If your tea comes in a resealable pouch that is not clear, you have the perfect container to store your tea. For those pesky tea bags in cardboard boxes, get them into a zip lock bag immediately and make sure you are using them regularly as they do not last that long. That is not to say you should not have a metal, plastic or dark glass container to store your tea, if you like those kinds of things. Just keep in mind they have seams and may not be as air-tight as most of the resealable pouches. Also, the flavor of the tea will stay with the container, especially plastic ones, so you have to be willing to constantly drink the same tea to justify having a secondary container for it. Either that or be prepared to wash it well between teas (and expect plastic to still retain the smell of the prior tea or soap used to wash it). Just remember to put your tea in a dark part of the kitchen away from heat, and not in the refrigerator, unless you have the tea in a vacuum sealed container. In closing, to keep your tea as fresh as possible, an air tight container that is dark and placed away from heat and appliances that produce heat or steam is the best solution.

Follow Dominion Tea: Facebooktwittergoogle_pluspinterestrss

Chinese Tea: Anhui Province

Leave a reply
Snow covered and jagged peak of Huangshan Mountain, Anhui Province

Huangshan Mountains in Winter in Anhui, China (by Flickr user miquitos, CC BY-SA 2.0)

The Anhui province of China is located in Eastern China, but does not border the sea. Roughly the size of North Carolina, it spans across two large watersheds, the Huai He and Yangtz rivers. Anhui is best known for its rich topography and natural resources. It comes as no surprise that the most drawn and photographed mountain in China, Huangshan, resides in Anhui. Huangshan mountain is also home to many of the wonderful teas that come from Anhui, including Huang Shan Mao Feng and Keemun. Anhui province teas are only a small reflection of this geographically diverse region.

History and People of Anhui

The Anhui province was not formally created until 1666 CE by the Qing Dynasty, which makes Anhui a rather young province in comparison to others. This may be due to the fact that Anhui is located in a transition zone between northern and southern China, so the land changed hands multiple times during wars between tribes. The terrain ranging from highland valleys, through mountainous terrain down to the deltas of its major rivers, makes for tough navigating, so its population is not as diverse as would be expected. Anhui is home to 59 million people (more people than the two most populated US states, California and Texas, combined). The vast majority of the population is Hui with the largest minority groups being the She and Hui.

The people of Anhui have influenced Chinese culture for centuries. Huiju opera was created in southern Anhui and is one of the most popular operas across China, often noted as the predecessor to the Beijing Opera. The highest quality materials for Chinese calligraphy also come from Anhui, including ink, paper and inkstones. Last, but not least, Anhui cuisine, consisting of wild game or fish with local herbs and prepared with minimal fuss is considered one of the eight staples of Chinese cuisine and of course their teas.

Anhui Province and Tea

Map of China with Anhui Highlighted

Anhui Province China

Huangshan Mountain and its surrounding region was named an UNESCO World Heritage site in 1990. This is very important as it will preserve the tea plants and fields in the surrounding region. In this region all six types of tea are produced but the highest quality teas from Anhui are really black, green, and yellow teas. The rich red clay and higher elevations around the mountain make perfect terroir for tea. Tea has been grown in the province for thousands of years and there are many tribute teas made in Anhui that never make it into western markets due to the high demand within China. The first plucking of tea that make Huang Shan Mao Feng goes for top dollar as well as their famous tea, Huo Shan Huang Ya, which was originally made as a tribute to Qing Dynasty. Keemun makes a fabulous black tea that was once part of the recipe for English Breakfast or common on its own in early American colonies, before the British planted tea bushes in India.

Ahui province is worth your time to learn about and if you are adventurous, take a trip and enjoy this beautiful area along with its tea.

 

Tea vs Coffee Imports – Who are the superpowers?

Leave a reply

About a year and a half ago we devoted some time to looking at the major tea producing countries around the world. As of 2011 data we saw, no surprise really, that China, India, Kenya, and Sri Lanka topped the charts as tea producing superpowers. Since doing this post I’ve had this nagging vision in my head that Germany reigned supreme on the tea importer side, being well known for their blending. Like last time I looked to the United Nations Food and Agriculture Organization Statistics Database for numbers on imports and this is where we return to look at import leaders.

Overall Tea Imports

The first thing to note right off is that the Russian Federation is actually the single largest importer, with nearly 400 million pounds of tea imported in 2012.  This is followed by the United Kingdom at 319 million pounds and, shockingly Afghanistan at 299 Million pounds. By sheer volume the United States came in fourth with 277 million pounds.  However, sheer volume of imports alone really doesn’t even begin to tell the whole story.  If you look at pounds of tea imported per capita you start to see a slightly different picture. By this measure Afghanistan (yes, really) imported over 10 lbs per person in 2012 followed by the UAE (8.75 lbs), Libya (7.76 lbs), and Mauritania (6.85 lbs).  The United Kingdom, which supposedly revolves around tea, came in at #7 with just over 5 lbs per capita, or half that of Afghanistan! And the United States…. well that would be #72 with 0.87 lbs per capita.

From the graphic below, which equates the imported tea per person to the number of cups it would brew you can see the United States sitting at 132 cups equivalent imported in 2012 while the top four countries have well over 1,000 each.

Tea vs Coffee: Equivalent Cups of Tea Imported per Person

Tea Importers:  Cups Per Capita (by cups brewed) – Visualization Care of Tableau Public

 

What about Tea vs Coffee Imports?

The comparison of tea vs coffee begins to highlight the east vs west nature of coffee and tea. Whereas the more prominent tea importers appear in the Middle East and Africa, this is very different with coffee where the dominant importers are Europe, Canada, and The United States of America.  Indeed on a cup equivalent of imports per capita America comes in 24th with 651 cups per capita imported.  Here too, however, we are far behind.  On a per capita basis, with over 4,300 cups per person, Luxembourg leads the pack followed by Belgium (4,110), Switzerland (2,530), and Germany (2,083).  Just so that we can re-affirm our dominance somewhere in the coffee vs tea imports area, let it be said that on sheer volume we win, hands down with nearly 3.2 billion pounds of coffee imported with Germany in distant second with 2.67 billion pounds imported.

Tea vs Coffee: Equivalent Cups of Coffee Imported per Person

Coffee Importers: Cups Per Capita (by cups brewed) – Visualization Care of Tableau Public

 

Tea Imports – The Whole Story?

While it might be satisfying to think that imports is a solid measure of popularity or consumption, that really isn’t the case.  In the world of tea and coffee imports and exports the numbers appear to be a bit cloudy. While we import a huge amount of coffee and tea, there are many countries, not known for growing either coffee or tea, which also export both products.  This is no different with the USA. While we import over 3 billion pounds of coffee we also export 320 million. Hawaii (which produces some great coffee and tea by the way) aside, the US isn’t exactly known as a coffee or tea producing superpower. Like coffee, while we import 277 million pounds of tea, we also export another 32 million pounds. And this, of course, doesn’t even scratch the surface on the various other products made from tea.

So in the end my assumptions about Germany being a tea importing juggernaut were very much busted. This quick look at import stats indeed revealed many surprises in both the large tea importing nations by volume and per capital as well as the dichotomy between tea vs coffee importing nations.