Truth or myth: Green tea and weight loss

Well it’s that time of year again when tea is peddled as a weight-loss product. Green tea is often the focus of this attention but a Cochrane review was published in December 2012. This work reviewed all the published experiments that had been done on green tea for overweight or obese adults. The conclusion was that “green tea preparations appear to induce a small, statistically non-significant weight loss in overweight or obese adults”. The study also concluded that “green tea had no significant effect on the maintenance of weight loss”.

The full text of the review is available here and it is worth downloading for the appendices alone. The rationale for the systematic review was to provide healthcare providers and consumers with reliable information on the impact of green tea in weight loss and weight maintenance. The authors only looked at randomised controlled trials (the most thorough of investigations). The studies were all at least 12 weeks in duration and compared green tea preparations with a control in overweight or obese adults who had no other health problems.

Bancha - Green TeaA search was done across a very wide range of databases (MEDLINE, CINAHL, AMED etc) for studies that investigated weight-gain and green tea in humans. The search was not limited by language and around 919 studies were found. 72 of those were relevant and 18 met the criteria of this review (randomised control trial with just green tea, greater than 12 weeks, on participants who were overweight but had no other significant illness) . In total 2,076 people participated in these 18 studies (ranging from 19 to 270 for each). Half of the studies took place in Japan with the other 9 conducted in Netherlands, Australia, China, Taiwan, Thailand and the US.

Higher weight losses were reported in the Japanese studies with eight studies reporting weight losses that ranged from -3.5kg to -0.2kg but overall, the author concluded that green tea produced a “very small, statistically non-significant loss of weight, decrease in BMI, and decrease in waist circumference” compared to those who did not have the green tea. The role of caffeine is not clear but there are some indications that the catechins in green tea, and not caffeine, may have been responsible for the “modest effect on weight loss”.

It’s not very encouraging for people who have started drinking green tea to help with weight reduction but swapping a double-mocha for a green tea would obviously be a different story.  And green tea does bring other health benefits so as the author says “even though the changes may be small, any small loss combined with minimal adverse effects may have an overall positive impact on an individual attempting to lose weight”.

Jurgens  TM, Whelan  AM, Killian  L, Doucette  S, Kirk  S, Foy  E. Green tea for weight loss and weight maintenance in overweight or obese adults. Cochrane Database of Systematic Reviews.  2012 Dec 12.

The Kombucha experiment – Part II

I’m tying up the loose ends of 2013 by writing Part II of the Kombucha experiment (see Part I here).

Since I the experiment started, I received a very kind offer of a SCOBY from the good people at l’Heure Bleue in Belgium. Unfortunately, security at Brussels Airport had other ideas about international trafficking of SCOBYs in containers that are larger than 100ml and sadly is was consigned to the bin.

In the mean-time, my own SCOBY seems to be doing pretty well. Three weeks after it started to grow, the SCOBY was thin looking but there was no mould and it had patches that were thick and white so I deemed it safe and went ahead a brewed my first batch of Kombucha.

SCOBY

I don’t know how important the rules of SCOBY-handling are but one of the most common rules is no metal touching the SCOBY so no spoons, jewellery, metal containers etc. Before handling the SCOBY hands should be clean but not with antibacterial soup. Cider vinegar seems to be the best way to clean your hands before handling.

Once you have successfully grown the SCOBY, here’s what is needed to prepare the first brew of Kombucha:

  • 200-300ml of the liquid that the SCOBY formed in
  • 2 litres of tea
  • 175g of sugar
  • A large, clean glass container
  • A tea towel and elastic band

Brew the tea by steeping the tea leaves in 2 litres of boiling water. Add the sugar and allow it to brew for at least 30 minutes. At this stage it is ok to use metal to stir because the SCOBY has not been introduced. Strain the leaves and pour into the clean glass container then leave to cool. It took around four hours for mine to cool to room temperature. Any hotter than this will harm the SCOBY but too cold is not good either (temperamental, these SCOBYs!!).

SCOBY in new homeOnce it is cool enough, slide the SCOBY into the large glass container and add approx. 300ml of the liquid that it grew in. The rest of the liquid that the SCOBY formed in can be discarded. Apparently it is safe to drink but is just very weak kombucha and not very tasty.

When the SCOBY is added it might float or sink or it might try some acrobatics with a half-floating manoeuvre, like mine did. It doesn’t really matter. Cover the glass container with a tea towel and elastic band and put it in a warm dry place.

 

Kombucha takes about 2 weeks to brew but the brew time can be adjusted to personal taste. It becomes less sweet with time but factors like temperature and surface area will also affect the speed of the process. Ideally, brewing should take place between 22 and 29°C. Mine is at 18°C so brewing time will definitely be longer.

Rehoming SCOBY

Once the first batch is ready you can bottle the kombucha and transfer the SCOBY (with 200ml of the brewed kombucha) to a new preparation of sweetened tea and the process starts all over again.

Kombucha naturally has very gentle carbonation that gives a tingling sensation but to get more fizz, let it sit in an airtight bottles at room temperature for a day or two. I’ve read about adding blueberries or ginger to boost carbonation but haven’t tried this yet.

Each time you brew a batch of Kombucha, a new SCOBY will grow adjacent to the original SCOBY. You can leave them together or separate to share with friends or start making jewellery!

Tea with food

food and teaThere will be plenty of eating going on over the next week or two and there are bound to be a few times when wine will need a substitute. Here are some of the basic guidlines on combining tea with food.

As a general rule, green tea is the savoury tea. Salt will bring out its flavour and crispness while sweet foods will bring out the astringency and bitterness. So vegetal green teas will go well with prawns, anchovies, other seafood and olives. It is better with light meats and snacks rather than greasy foods. Light salty crackers like water biscuits work well and especially crackers with thyme. Light rice-based dishes are also complemented by green tea.

Strong black tea (from Africa, India and Sri Lanka) goes very well with red meat and spicy dishes (especially peppers) but goes equally well with rich creamy deserts, cream cheeses, dark chocolate and nuts such as pecans. Tea with desert is quite common and black tea is ideal for deserts such as rich chocolate cake or pecan pie.

It seems a shame to eat food with oolong but if you must then lighter oolongs go well with seafood, salty crackers and walnuts. Salty crackers with rosemary go particularly well. Similar to green tea, lighter oolongs do not combine will with heavy foods that contain butter and fat. Dark roasted oolongs go well with rosemary, honey, pecan, almonds and cashew nuts.

In my opinion pu-ehr should not be drank with food but shou pu-ehr is very soothing after a heavy meal.

White tea doesn’t blend well with food but I’ve heard it can be used as a palate cleanser between courses instead of sorbet (I’ve never tried this).

For the tisanes, rooibos and honeybush have a natural hint of sweetness so they go well with pastries and chocolate. Christmas rooibos usually has cinnamon, spices and orange that complement fruit cake, pudding and mince pies.

Finally, fennel, peppermint, ginger and anise are all excellent for aiding digestion. Anise is sweet and spicy and calming for digestion at night time while fennel is particularly good after a heavy meals and for helping with heartburn. Fennel and ginger are also excellent for nausea.

Stale tea

Last weekend we spring-cleaned the kitchen (we are late for 2013 spring cleaning not early for 2014!). In the process, I found some very old matcha, which makes for an interesting comparison with the fresh matcha that I bought last week.

Matcha - Fresh and StaleHere are the photos. You can see that the fresh matcha is striking bright green but the old one is a dull, grey-green. Tea doesn’t spoil with time but it does loose its flavour and colour especially if exposed to air. Matcha is one of the brisker tea on the fading process. Ideally it should be used within a few weeks of opening but keeping it in an airtight container in the fridge can extend this a little. I’m ashamed to say that the old matcha was not in an airtight container, not in the fridge and has probably been on the shelf for well over a year. In other words, a perfect storm of matcha degradation!

 

The old matcha still has a strong vegetal aroma but it doesn’t form the nice froth and the taste is unpleasant and slightly sour.

Brewed Matcha - Fresh and Stale

Not all the examples of stale tea are as obvious as matcha and of course it varies with vacuum sealing, conditions etc. but here are the general rules that I use:  greens: within 4/5 months (of the harvest date), light oolongs and early Darjeeling: within 6/7 months, black tea (apart from Darjeeling) within 12-18 months, pu-ehr and heavily roasted oolongs: whenever they’re ready – both improve with age.

For the teas that don’t age, I have a terrible habit of not drinking them quickly enough. When I find a tea that I love, I sometimes wait until I can make enough time to really enjoy it, or the right occasion, or someone to share it with. Some fine teas have been lost in this way and the matcha was a good reminder. From now on, I am going to be dedicated in keeping my tea list updated with the date of purchase/harvest. That might sound nerdy but it’s nothing compared to the plans I have for rules in excel and automatic colour coding depending on the best time to drink ;-).

The Kombucha experiment – Part I

As usual, I’m a couple of years behind the trend. Kombucha is a drink that was extremely fashionable a few years ago but it still has a solid following. It is a tea drink that is made by fermenting sweetened black tea with a culture of yeasts and bacteria. It is also known as Tea Kvass (Russia), Hongchajun (China) and Kocha Kinoko (Japan). Confusingly, in Japan, Kombucha refers to seaweed that is powdered to produce kelp-tea. The two “kombucha” are very different.

Many websites talk about  probiotics and the detoxification and immune boosting properties of Kombucha (see notes on health at the end of article) but it also happens to be a very tasty drink that is naturally carbonated.

DBKB KombuchaWe are lucky in Dublin to have a local, organic, non-flavoured, Kombucha “brewery”. This is a very convenient option especially if you are short on time but I’ve never been one to take the easy route so I decided to experiment and try brewing my own.

A SCOBY (Symbiotic Culture of Bacteria and Yeast) is needed to prepare Kombucha.  The SCOBY is sometimes called a mushroom but it’s just a colony of bacteria and yeast – no fungus. I’ve looked at lots of websites with instructions on how to brew Kombucha and almost all of them say that you start with a SCOBY. I was having some trouble locating a SCOBY but then I came across an article that said you could grow your own SCOBY so I decided to try that. I don’t know how this is going to turn out- we have to wait for two weeks to see if it works or not but here were my steps for preparation.

Kombucha IngredientsI brewed 500ml of tea. I would have preferred to use an organic black tea but I had none so I used a regular Panyong Golden Needle. I left it to steep for 10 mins and then removed the tea leaves, added 1 tsp. of sugar and allowed it to cool for 30 mins. I have since read that heat can be very destructive to the whole scoby-growing process and at 30 minutes it was still warm so this could be a problem. Leaving it for an hour would be a safer bet.

After 30 minutes I added 330ml of raw Kombucha (I used DBKB).   After adding the Kombucha I covered the bowl with a tea towel and put it in a warm dry place. I used a glass bowl because apparantly the acidity of the tea can cause it to absorb harmful elements from containers that are painted, ceramic etc (there has been two reported incidences of lead poisoning where Kombucha tea was brewed in a ceramic pot).

And now I have to wait for 2-3 weeks….

Health Note: Since the early 19th century, Kombucha tea has been promoted as an immunity-boosting tea that can strengthen the body and prevent many ailments. There is no solid scientific evidence to support the health claims of Kombucha tea.  In addition, there are potential health risks from Kombucha (source) but these equally, are not backed by solid scientific research. Because of the potential health risks, people with an immune deficiency or any other medical condition should seek medical advice before drinking the tea. Women who are pregnant or breast-feeding should not use this tea.

Matcha

Matcha (or maccha) is a uniquely Japanese tea that comes as a finely ground powder. It is a green tea, but unlike most teas where the liquid is poured off the leaves, with matcha the powder is whisked into the liquid and ingested whole.

Matcha and chasen (bamboo whisk)

Matcha is made from the tips of budding tea-bushes that have been shaded with bamboo mats (or black tarp) for approximately three weeks of their spring growth. Less sunlight means less photosynthesis, which is how the plant generates energy and grows. Under the shade, the tea plants spread out and become thin and tender. They compensate for the lack of sunlight by increasing the amount of chlorophyll. Chorloryphyll is a pigment that absorbs red and blue light but reflects green (hence the green colour) so increasing the chlorophyll gives the leaves a bright green colour. After picking, the leaves are steamed, air dried and the main part of the leaf are separated from the stems and veins to produce tencha. The tencha is then ground using granite wheels to make the bright green, fine, matcha powder.

The video from o-cha.com shows the covering of the tea plants with bamboo and straw, the shaded hand-plucking and then the processing that takes place afterwards to make both gyokuro and matcha.

Matcha generally comes in three grades. The highest grade is Koicha (thick tea) and this is used in Japanese tea ceremonies to make a dense, viscous tea. Usucha (thin tea) is the second grade and it is used in Japanese tea ceremonies to make a more diluted thin tea with frothy foam. Finally, cooking matcha is used as an ingredient to make food like matcha ice-cream, cakes etc.

Matcha has the reputation of going stale quickly so if you are making the investment (matcha is a comparatively expensive green tea), it is worthwhile paying a little extra for a good quality matcha that is fresh. Matcha is not something that I will always have in the house. I’ll generally buy about 35g and then drink it every day until it’s gone (known in my house as the matcha-spree!).

To prepare matcha you will need a bamboo tea whisk (chasen). It is also helpful to have a tea bowl (chawan) and a tea ladel (chashaku) but these can be substituted with a flat bottomed bowl and a teaspoon. The bowl is pre-heated, then dried and about 2g of matcha powder is added with the ladel. Some people sieve the matcha to break the small lumps but I just break them up with the tip of the whisk. Water at approx 80°C is added and then the mixture is whisked until smooth with a back and forth motion (like writing a “W”) rather than a circular motion. The matcha is suspended in the hot water during whisking (not dissolved) which means that matcha particles will settle to the bottom of the bowl if it is left to stand so enjoy immediately.

I bought my current batch of matcha (Ishikawa Matcha) in Postcard Teas, London and it cost £20 for a 40g refill pack.

Masala Chai

Spices for Masala ChaiMasala Chai is spiced and sweetened milk tea. It is mostly associated with India but until the 1900s the spicy mix generally did not contain black tea. In India it is available at every market all year round but for me Chai is a seasonal drink that starts in late October and continues through winter. Its spicy malty heat is perfect for cold winter days.
There are several ways to brew chai – milk only, milk and water, ground spices, whole spices etc. The list of spices varies greatly but black pepper, cardamom, cinnamon and cloves seem to always form the foundation. Below is the recipe that I use with some of the health benefits of the spices. This is customised to my own preference for spiciness/sweetness – experimentation is needed to make your own version of Masala Chai.

Masala Chai

  • ½ cinnamon stick [warms the body and enhances digestion, especially the metabolism of fats]
  • 1 tsp. ground cinnamon
  • 7 whole cardamom pods bruised with pestle and mortar [stimulates digestion]
  • 7 whole cloves [antiseptic and anti-parasitic properties and digestive aid]
  • 7 thin slices of fresh ginger [colon cleansing, stimulates circulation, protects the liver and stomach]
  • 10 black peppercorns, ground
  • ½ tsp. grated nutmeg
  • 2 cups water
  • 2 tbsp. honey [natural antiseptic, promotes energy and healing]
  • 1 tbsp. assam (or other strong black tea)
  • 1 cup low-fat milk

Put spices and water into a small saucepan and bring to a boil. Cover and simmer for 5 minutes. Remove from heat and set aside for a further 5-10 minutes. Add honey and return to the heat again to bring to a boil.

Add tea leaves, remove from heat and set aside for 3 to 5 minutes. Strain through a sieve and then add milk. Heat the full mixture over low heat then serve immediately and enjoy!

Plucking Tea

When tea is harvested, different parts of the plant are plucked, depending on the quality of the tea to be produced, the type of tea, the country etc. Tea picking is an important stage in tea processing and historically much has been written about the activity and the women who carried it out. Chatterjee (reference below) for example, mentions one account of labour management in the Tang Dynasty where tea pickers were required to abstain from eathing fish and certain kinds of meat so that their breath might not affect the bouquet of the leaves. He also talks about how women’s hands and fingernails were inspected to ensure body oils and perspiration would not contaminate the leaves.

Today, it is generally accepted that for high quality orthodox tea, the leaves at the tip of the stem are hand-picked. Plucking the bud and adjacent leaves  encourages new shoots to grow. Dexterity and speed are required, as the pickers snap the top, tender stems using the index finger and thumb and breaking the leaves off with a quick snap although many farmers have adopted the time-saving method of attaching a blade to the index finger for snipping the stem.

 

tea pluck types: imerial, fine, average

Image Source

The tender leaves at the top of the plant are the freshest growth and the most tender and are the richest in catechins and theanine. Imperial plucking involves just the bud and one leaf. Fine plucking takes the bud and the two adjacent leaves at the top of the plant stem. Average plucking takes the bud and three leaves.

 

 

Below are two photos of a jasmine pearl tea. The photo on the left is before steeping and the one on the right is the unfurled leaf after steeping. The beauty and perfection of the unfurled bud with its adjacent leaf or two leaves strikes me every time I make this tea.

Jasmine pearls before and after steeping

 

Reference:
A Time for Tea: Women, Labor, and Post/Colonial Politics on an Indian Plantation  By Piya Chatterje, Duke University Press Books, 2001

Tea tasting on the radio

Last week I received an invitation from Louise Walsh at LMFM to come into their studio and do some tea tasting with presenter, Deirdre Hurly on the radio. It sounded like a great idea but I’ve never done tea tasting on the radio. What could possibly go wrong (apart from drawing a blank on a really obvious question or scalding the presenter with a pot of tea)?

Selecting teas was a challenge though. I didn’t want to start messing with different temperatures so I chose only teas that would need boiling water (i.e. no green or white tea). Myself and a friend spent an afternoon drinking 20 teas and debating the merits of each. We both got jittery from caffeine but decided on one tea and one herbal infusion that the presenter would probably know (earl grey and rooibos) and two teas that she probably wouldn’t (Taiwanese oolong and a pu-ehr).

During the interview I more or less forgot I was on radio, which was great but it also meant that I kept forgetting to describe the various leaves and liquid. Tea tasting involves smell, sight, taste and touch much more so than hearing so I was handing the cups and dried leaves and wet leaves to Deirdre (as I would in a tea tasting) and she described it to the listeners. She was very patient!

I tried to have all the teas brewed beforehand to avoid spillages and calamities but trying to unpack all my equipment and prepare the teas in 80 seconds before the show was a lot of pressure. Next time I’ll brew as I go.

The 20 minute clip (below) can also be downloaded here or the full show from Friday is on the Late Lunch podcast page.

My thanks to Louise Walsh and Deirdre Hurley of the Late Lunch for being so welcoming and fun. No presenters were scalded during the making of this interview ;-).

7 types of Earl Grey

Earl Grey is a black tea that is flavoured with oil from the rind of bergamot orange, a fruit grown in Italy, France and South East Asia. Variations on the traditional blend include Lady Grey (a blend of earl grey with blue cornflower blossoms), Russian Earl Grey (Earl Grey with pieces of citrus peel and lemongrass) and Red Earl Grey (rooibos and bergamot).

Charles Grey - 2nd Earl Grey

Charles Grey – 2nd Earl Grey (Source)

Responsible for the name of the tea is Charles Grey. Charles was an English aristocrat who was educated in Eton and Cambridge and elected to Parliament at the age of 22. He married Mary Elizabeth Ponsonby (daughter of Baron Ponsonby of Imokilly, Co. Cork) and had six daughter and ten sons. Before he was married he had an illegitimate daughter with the Duchess of Devonshire, which is the subject of the movie “The Duchess”. He was prime minister of England from November 1830 to July 1834 and inherited the title of Earl from his father. Charles Grey was noted for advocating Parliamentary reform and Catholic Emancipation. Two of his most notable reforms were the Reform Act of 1832 and the Slavery Abolition Act of 1833 but interestingly the monopoly of the East India Company in Britain’s trade with China ended while he was prime minister.

 

1928 Advertisement for Earl Grey

1928 Advertisement for Earl Grey (Source)

How he became associated with the tea is unclear. There are stories of good deeds in China that resulted in the recipe for the tea coming to his ownership. Another version tells how the blend was created by accident when a gift of tea and bergamot oranges were shipped together from diplomats in China and the fruit flavour was absorbed by the tea during shipping. Yet another version of the story involves a Chinese mandarin friend of the Earl blending this tea to offset the taste of limescale in the water at his home (at Howick Hall). In reality, it is not absolutely clear why the tea was named after Charles. However, the tea was served by the Greys when they hosted gatherings and Jackson’s of Piccadilly say that they introduced the blend in 1836 to “meet the wishes of a former Earl Grey”.

As a person who claims to not like flavoured tea, I currently have seven different varieties of Earl Grey on my shelf. Last Saturday I brewed all seven to compare and contrast. Among them were four loose leaf teas, one whole-leaf tea bag and two CTC tea bags. Historically, Earl Grey has a reputation for involving low quality teas that are masked by the bergamot  but each of these was absolutely drinkable and most of them were very pleasant. Going through the distinctions of each would get tedious so I’ve shortlisted the best of the crop.

3 of the 7 earl greys

The nicest tea was a blend of Chinese black tea from Tea Palace. It was a beautiful earthy tea that was balanced with a gentle bergamot flavour. Second place went to a blend from Damman Frères. The presence of blue cornflower blossoms and sunflower petals means that technically this is a Lady Grey but it was sold as Earl Grey so we included it. The Chinese black tea in this blend stood up well with the bright citrus flavour and again gave a harmonious flavour. Of the two CTC teabags, the Marks and Spencer brand was the more interesting of the two. It used a Sri Lankan black tea that gave their blend a rich, powerful base.

The most interesting conclusion from tasting all these teas is that aroma of the loose leaf gives very little indication of the taste. The strong perfume smell of the Dammann Frères was off-putting but that overpowering fragrance did not translate to the taste. Similarly, one of the teas was an earl grey lavender and the aroma was distinctly soap-like. But again, that soapiness did not translate to taste.

Some notes on preparing earl grey tea: Freshly boiled water should be used. A steep time of 1.5 minutes is good for the loose leaf teas (3g tea and 150 ml water). The CTC tea bags steep in 40 – 45 seconds (200 ml water). All the teas were drank black.