Q. Green Tea Vs Black Tea - Can you give the basic differences?

Almost all Tea manufactured in Sri Lanka until recently were Black Tea. There was only one factory which produced a type which differed. The tea manufactured at Lethenty Tea Factory till 1970’s was called ‘Green Tea.’ I had the opportunity to taste that long time ago, and remember the particles to be greenish black in color. They looked like finely cut tea leaves and I now reckon the tea manufactured by Lethenty was something called Laurie’s Tea Processor (LTP) method, where the green leaf goes into ‘cutters’ instead of rollers. I am not sure if any factory in Sri Lanka still makes this type. I am unable to go into the details of this particular manufacture as to my knowledge there is no factory doing this at present in Sri Lanka.

I was told Lethenty teas were only meant for export to USA and throughout my experience with Tea, I notice American prefer Green Tea to traditional Black Tea.

Now let me come to the difference between the real Green Tea Vs Black Tea. The difference is not in the type of green leaf, but the type of manufacture, and Fermentation or Oxidation process in particular.

• Black tea is something where the enzyme has fermented. In simple form, the enzyme with the juice inside the tea leaves. When it is fermented – fermenting takes place when oxygen is allowed to act with the enzyme; this is how all desired attributes come into the tea. If it doesn’t ferment, the tea will be plain. • For Green Tea we don’t ferment the way it is done for Black tea. However, the leaf has to go through other rolling process. The basic thing we do is to ‘kill’ the enzyme in the leaf or make it inactive, so that when oxygen comes into contact with it, no fermentation takes place. Yet, all the aroma and qualities are preserved in their undiluted form within the tea. • During fermentation, the aroma and other attributes get altered into different compounds. When no fermenting takes place, all these qualities get preserved in their purest form. These qualities are found to be very good for health which cannot be found in black tea.

Q. Why is withering so important in relation to Green tea Vs Black tea?

Withering is the first process the green leaf undergo within the factory. For the best quality made tea, the factory needs the best standard of green leaf. Many people have a false assumption that a ‘good factory manager can make good tea out of any raw material.’

First of all we must get the best possible standard of green leaf from the field. The best leaf will be – a bud and two leaves, of the correct size. We can have bud and two leaves from a very young bush, e.g. tipping leaf just after pruning, but it will have less tea quality, as most of it will be water and the dry matter will be about 15 to 20%. Therefore, the leaf – bud and two leaves must be of the correct size, and harvested at the correct time - harvest after two or three months of pruning will not be the correct time for high quality tea - and correct weather conditions. The ideal weather conditions for best quality tea will be dry months with cool nights during which time the leaf will have more flavor compounds in them.

• When you wither leaf by some method you reduce the moisture content of the leaf – which is the unopened bud with the two leaves together with the un-matured stalk. Normally this will have 70% to 75% moisture and the balance 25% to 30% will be the dry matter. If you take about 100 grams of green leaf and bake it, you will get only about 25 to 30 grams of dry matter.

• During withering, we reduce the moisture by 45% to 50%. During the dry months, or the flavor season, if you examine the leaf, you will notice the leaf surface will be harder, as the leaf outer cells become a natural barrier to withstand the harsh sunshine, giving a natural protection to the interior. The stomata close up to reduce the moisture escaping, creating a stress on the leaf. The more the stress, the better the flavor will be. Automatically, when the duration of withering is less, the flavor will be better.

• In wet months if withering takes 15 hours, during dry months the same withering can be achieved within 8 to 10 hours. Withering duration is very important because during wet season, it not only reduces the moisture it will also give sufficient time for chemical changes to take place within the leaf. This is why factories which give more importance to withering, produce better teas throughout the year than those who do not. The duration must strike a balance for the leaf to physically reduce moisture and for the chemical changes to take place.

So during wet months wither between 15 to 18 hours and during dry months 8 to 10 hours is recommended to achieve the correct wither. During dry season, nights will also be dry with lesser humidity, and losing moisture will be faster.

Q. Tell me the type of Rolling you say best?

You can reduce the moisture content to such a degree, where it can act on the leaf, when you remove about 45 or 50% of the moisture, the leaf will be very supple, droop but will not break. This is the condition we aim. What we do is concentrate juice inside the leaf, which preserves the enzymes etc. Now we have to bring the juice out by rupturing as many cells as possible thus exposing the enzymes to the oxygen of the atmosphere.

How do you do this? No.1 – the normal, old system of Rolling. You roll the leaf for a certain period and then pass thru the Rotorvane again and again. In between you separate broken small particles using a Roll Breaker and separate the unbroken particles again subject to the same rolling and passing thru the Rotorvane, four or five times, until the bigger stalked particles reduce in size to the minimum.

• As small particles are separated, we spread it on tables or separate floor areas, or Fermenting Machines and we give a certain period of time for the oxidation to continue. It can take half or three and half hours. This depends on the elevation of the factory, type of leaf, and depending on the type of liquor that you desire. Remember, shorter the fermentation period, you will have a little more flavor, but less color and strength. Again, after longer fermentation, you will have more color, more strength in the liquor but less flavor. So we have to strike a correct balance, to have the optimum color, flavor and strength, which make the best quality tea.

Q. What exactly happens during Rolling?

During hot weather or strong windy conditions, the outer surface of the leaf becomes harder, which is a natural process. This is why the leaf needs a little harsher treatment at the initial stage. If you take a cross section of the leaf, you will see below the outer surface, a different set of enzymes and the next layer will have another different set of enzymes in it.

• During rolling we mix all these enzymes together. During withering the moisture cannot escape from inside or any other side, it has to travel from cell to cell, come to the surface and then escape. As in osmosis, the most diluted form moisture comes to the surface and the more concentrated juice remains underneath.

• At the initial rolling, it is important that we damage the outer layer of the leaf first. During rolling we allow the juices mix up among them. The outer surface takes longer time to ferment than layers below. The outer surface will not act with oxygen as quick as the inner ones and must be given at least 30 to 45 minutes more time to oxidize. If you mix up all the enzymes together at the initial stage itself, the flavor and quality you are looking at will not be achieved. For this reason we do the ‘condition rolling’ to damage the outer cells only and then allow it to ferment.

Q. Some points on Fermenting and Drying for Green tea Vs Black tea?

The person who is monitoring the process will know exactly the optimum level of fermentation. Say, after an hour he may find it necessary to ferment for another half an hour or even more to achieve it. Once the required level of fermentation is achieved, the tea will be ready for “ARRESTING” further fermentation which is done by sending thru a Fluid Bed Drier at a certain high temperature of around 140 to 150 deg F. To get this temperature to the tea, the temperature underneath must be about 250 F.

• Earlier, we used trays to carry fermented leaf to dry them by blowing hot air underneath the trays. The air that comes out carries out a certain amount of moisture. By such means, the actual arresting of oxidation is not 100% accurate. The wettest tea must get 125 to 130F for which we must give 150F to arrest fermenting. This ideal temperature of 75 to 80F will allow ferment to take place very fast. This is done on a normal drier. On a Fluid Bed Drier to one long chamber we give very high temperature at the bottom, the first stage itself where the green leaf falls, will get a temperature of 240F to 250F. Straight away the fermented tea gets the high temperature, with correct pressure, and a heavy volume of hot air blows the tea up, it will travel to about 18 to 24” up.

• Though the temperature given is high, the actual temp of the tea particles at this stage will be around 140 or 150F. About 60% of the drying takes place at the first stage. Now the tea is sent to the second stage where another 25 to 30% moisture is taken out. When it comes to the last stage, the temperature will be much lesser. The tea is now almost dry with only another 10% moisture to be taken out. At this stage the tea will receive lesser temp and conditioned to last a longer period. What comes out is the black tea at a temperature of about 140F.

• The whole process on the drier will complete within 18 to 20 minutes. The hot tea is allowed to cool for a short period, not in a humid area, as it is so hygroscopic, it will absorb any smoke, aroma and moisture in the atmosphere quickly. Care must be taken to avoid it absorbing such matters.

Q. What happens to the tea at this stage?

For black tea, after condition rolling, most of the upcountry estates follow Rotorvane. They pass the initial bulk after it comes out from condition rolling into Rotorvanes, in a continuous flow.

• Within five-six minutes it comes out in a mashed state and dropped into Ball breakers to break lumps and allowed to travel slowly on conveyors to fermentation tables. Maximum time is allowed for fermentation to take place. After five or six minutes on the bench, it is sent to another set of rotorvanes, same process is repeated. Only after two or three rounds Roll breaking is carried out. Smallest particles are removed. Bigger particles go again for rolling and roll break. 30 to 40 seconds taken to separate the larger and smaller particles. Large particles sent to another rotorvane to finish the process.

• In Low country, after rolling, tips are removed using No. 4 Mesh, to take out larger particles. In Upcountry they use smaller size meshes No. 7 or 8 for extracting smaller particles. The tea is sent for second roller, giving a little more pressure, not full pressure like in upcountry.

• Now the bigger particles which refused to be broken up will be the ones with harder stalk and particles, but they will have retained more color due to longer fermentation. They will be fired separately without mixing up with the smaller tea.

Q. Are there basic differences between Upcountry and Low Country manufacture?

In orthodox Low Country manufacture they make larger particles. They give many lighter rolls as required under this method. They take out only the buds and smaller tips and manufacture the main bulk separately. Unlike Upcountry manufacture, they separate every different kind for different grades. They break up the smaller particles to produce FBOPF. Only the leaf will form Pekoe, only the long stalk as OP, the smaller stalk BOP, etc.

• For Low Grown manufacture, fermentation period is much longer because all the juice is not extracted, as the leaf is fairly large, the cells are not 100% ruptured. So the enzymes are right inside. There is no way of sending oxygen in. The tea is left longer on the fermenting table in high grown areas than in low country, as oxygen availability in the atmosphere is more in Low country than in Upcountry. But the quality of the sun subjected on leaf is poor because they grow plenty of shade trees in low country. This prevents leaf from getting all the sunshine and in turn produces more chlorophyll. The more chlorophyll, after manufacture the tea will be blacker than leaf plucked from Nuwara Eliya area. That is why though NE tea has more flavor, the tea itself is brownish. People who love flavor tea do not bother about the appearance. They only want that special NE aroma.

• NE tea is almost equal to teas produced in Darjeeling, where tea is plucked only 7 or 8 months a year. Their factories are closed during winter season. When they resume harvest, they get the best of flavor tea coming out. This is why we use the term first flush and second flush etc. The same is in NE. Tea produced after a period of harsh hot weather, usually gives such flavor we can drink it without milk or sugar. Unfortunately, the quantity at that time will be very less. However, we can produce 75% of such teas right throughout the year, as NE is cold throughout the year. With my own type of manufacture, I was able to keep record tea prices at Pedro Estate, for over ten years.

Q. Have you tried out Green Tea manufacture Vs Black tea in your factories?

I have not done any commercial scale Green Tea manufacture in the factories I worked, but have tried out some methods when we first heard about Green Tea.

• Green Tea can be manufactured using two different methods; one is the Panning System and the other by Steaming System. Panning is destroying enzymes in huge iron pots. This is the Chinese system.

• Remember all other matters, like plucking and standard of leaf apply to Green Tea the same as for Black tea. The main point to note is there is no withering initially for green tea manufacture. As soon as the leaf arrives at the factory, it is either sent to the Pans or to the Steaming Machine. If it is on Steaming system, there is a short period of withering just to remove the moisture. Then normal cutting or chopping of leaf takes place in different types of machinery. The rolling process here is done on a different machine.

• After Panning, some factories use Roller for initial twist and curling. They are then sent to special machines for shredding and cutting as required to make the leaf smaller. Rotorvane is not used for Green Tea.

• The purpose is to make the large leaf into smaller particles. As it gets rolled, it is dried. After drying, it is rolled again. Finally, it comes out in a mixture of all sizes of tea. In the process itself there are units of drier to dry the leaf. Rolling and drying in a drier is repeated, until the dry tea comes out in the correct temperature required. Because there is no fermentation, no enzyme reaction or oxidization on enzymes takes place in these methods. Due to this reason, the tea remains GREEN in color and does not turn black. The enzymes have been deactivated by depriving oxygen acting on them.

• The tea is preserved as it is and therefore it will not have a strong color as in black tea. It will have a light greenish yellow color. However, it will be very aromatic and pungent as there has been no fermentation. If you take some green leaf and chew it, you get a certain taste and smell and you will find the same in made Green Tea. In other words, the basic characteristics do not change.

All other procedures, such as grading remain the same as for Black Tea, but they are normally packed in smaller bags for the convenience of buyers.

Q. I know you don’t do marketing, but can you say something about Tea Marketing?

Originally Sri Lanka was selling only bulk tea. Nowadays, several firms do blending of tea in country. Most of their teas are exported in ‘value-added’ form. They will have their own brands, with unique flavor, color and strength unique only to them, to suit their customers. They achieve this by buying certain types of tea from different gardens, and blend proportionately until they get their own blend. They pack it after that. That particular kind of blend will not be available by any other blender.

• Some firms blend for special fancy packing, such as ceramic containers, gold or wooden cups, coconut leaf or earthenware containers and sold at higher prices. This gives much boost to cottage industry of Sri Lanka. You can find such beauties at star-class hotels, airports and various retail Tea Centers. These specially packed teas have a good export market as well.

Q. Finally, what is your message to young manufacturers?

Be thorough with the basics. Although the industry has introduced numerous latest machinery the basics of tea manufacture remain the same. If you follow the principles correctly and add up with modern machinery, I am sure you can produce a good standard of quality tea.

Go to Tea Manufacture for Green Tea or Black Tea process