Growing Tea?

I got a letter this morning from the County Council about my allotment application. I have been offered a lease on a 10m x 20m “transition” allotment.

The plan is keep it simple with carrots, spinach and maybe potatoes but for future years I have noted that there is nothing in the lease agreement that prevents me from starting a tiny tea plantation so I did some investigations. Most of us have heard of the decorative camellia plant but the tea variety (Camellia sinensis) is becoming popular for gardeners. Although it prefers subtropical climates the Camellia sinensis plant is both resilient and adaptable.It is an evergreen shrub but can grow up to 17 m high. In cultivation, it is usually kept below 2 m high by pruning. Its bright green leaves are shiny, and often have a hairy underside. Its fruits are brownish-green and contain one to four seeds.

The fragrant flower of Camellia sinensis

The fragrant flower of Camellia sinensis (Source)

There are three major varieties: Camellia sinensis var. sinensis (Chinese tea),  Camellia sinensis var. assamica (Assam tea, Indian tea) and Camellia sinensis var. cambodi  (Java tea). It seems that Chinese camellia is the original tea plant and is hardier than the other varieties. It has relatively small and narrow leaves and produces fragrant white flowers in autumn. Given the right conditions, a tea plant can grow and produce for 50-100 years.

C. sinensis var. assamica is taller in its natural state and can grow into a loosely branched tree to a height of about 17 m. It is a less hardy variety with medium, droopy, leathery leaves. It needs well-drained soil and needs ample water but it is the most cold-sensitive camellia.

Camellia sinensis var. cambodi is used to create hybrids and not grown on its own so much but it can also grow quite tall and has the small white flowers when temperatures cool in autumn.

Tea can be propagated from cuttings or from seeds but the seeds take extra time. From seed, it will take 2-3 years to be ready to harvest. The plant likes regular harvesting and the new shoots can be used for tea. They need to be properly pruned back every four years to rejuvenate the bush and keep it at a convenient height.

Camillia sinensisFor planting, Camellia sinensis likes well-drained, sandy, acidic soil but will do well in other soil types too. They grow well in sunny areas but light shade develops the flavor of the leaves. They should be kept 1 meter apart to avoid competition. Camellia bushes are drought-tolerant and will survive dry summers. The problem for Irish weather conditions is that they need to be kept in a dry atmosphere to avoid mildew developing and the plant prefers “not very frosty dry winters”. Ideally, day temperatures of ~25 °C and night temperatures of >10 °C. Considering it is the end of March and there was snow on the ground here this morning, I’m guessing they would need to be kept in a greenhouse or indoors for most of winter and spring to survive.

I notice that there are a few tea plantations in the UK (Cornwall, Kent Pembrokeshire) so it seems that it is definitely possible to grow Camellia sinensis outside a subtropical climate. I might give it a shot at some stage but probably just as an experiment in a pot so I can move it indoors.

Tea-drinking in Early Nineteenth Century Ireland

There is an interesting paper here by Dr Helen O’Connell, which discusses how tea-drinking in Ireland was viewed in the early nineteenth century.

Tea was first introduced to Ireland in the mid 18th century and at first its cost kept it a luxury that was confined to the upper class and aristocracy. The cost of tea fell significantly in the eighteenth century and the removal of tariffs in 1784, the price was halved again. Tea smuggling was widespread and it was the smuggled, cheaper tea that Irish peasants enjoyed. Its popularity grew quickly and by 1830s, tea was in staple in people’s diets and widespread amongst the poor. It seems that English reformers saw the pastime of tea-drinking as “reckless and uncontrollable” and something that could cause “addiction, illicit longing and revolutionary sympathies”.

The rural workers in Ireland were seen as decadent and lazy and tea-drinking promoted these flaws in the lower classes. It was deemed that the consumption of tea was something that would “deepen the social backwardness seen to be endemic and unmanageable in rural Ireland”. The practice was seen as particularly distracting for women and elimination was necessary so they could focus on their homely duties and the prospering of the economy.  Behind these objections seems to be a theory that tea drinking would make the Catholic Irish appear more Irish (and less English). In addition, the symbolic equality attained by tea-drinking “could only prepare the ground for the eventual attainment of actual equality” which might render the reform impossible.

Dr O’Connell says that “the prospect of poor peasant women squandering already scarce resources on fashionable commodities such as tea was a worry but it also implied that drinking tea could even express a form of revolutionary feminism for these women. If that wasn’t enough, there were also supposedly drug-like qualities of tea, an exotic substance from China, which was understood to become addictive over time.”

Cottage Dialogues (1811)

Cottage Dialogues (1811)

English reformers distributed pamphlets to peasant households that condemned the drink and highlighted its dangers.  They emphasized the frivolity of wasting money on a substance that had no nutritional or practical benefits.

Mary Leadbeater, Cottage Dialogues, 1811

“Now if you both take to drinking tea, (and sure you can’t sit down to one thing, and he to another,) you must have a quarter of an ounce of tea, that is three half pence at the lowest; and two ounces of sugar, that is three half pence more; a four- penny loaf will be tight enough; two ounces of butter two pence; all that comes to nine pence, and hardly enough; and weak food for a man.”

While economic historians interpret tea drinking as a sign of wealth, Leadbeater attempts to interpret the practice as a sign of backwardness and an inability to manage the domestic economy.

Reference: O’Connell H. ‘A Raking Pot of Tea’: Consumption and Excess in Early Nineteenth-Century Ireland. Literature & History. October 2012;21(2):32-47

Oxidation

I briefly mentioned oxidation in my getting sorted post when I was talking about the different categories of tea and thought it might be worth talking about a little more.

Oxidation is basically what causes the leaves of the tea plant (that are green when they grow) to turn brown. It is a biochemical reaction which involves the absorption of oxygen (like when an apple is cut). Black tea is generally close to fully oxidised, Green teas are usually non-oxidised and Oolongs tend to be partially oxidised to varying degrees. Oxidation is pivotal to the processing of tea and will change its colour, smell and flavour.

Oxidation Chart

Oxidation Chart (Source)

Oxidised teas, are bruised (from lightly to extensively)  to break the  cell walls and allow the enzymes in the leaves to cause natural oxidation reactions. Heating the leaves stops oxidation by deactivating the enzymes. In this way the tea producer can decide on the extent of oxidation by introducing heat. Green teas are non-oxidised and so are heated early in the production process so that the oxidation process is skipped.

Sometimes tea-oxidation is called fermentation but no microorganisms are used so this is a misnomer. Generally when people talk about tea-fermentation they are talking about oxidation.

However, just to complicate matters, the proper micororganism fermentation does take place with pu-erhs.

There are exceptions to this, but here are the usual oxidation and fermentation levels:

Black tea – almost fully oxidised

Oolong tea – partialy oxidised (ranging from 12% – 80%)

White tea – minimal oxidation

Green tea – No oxidation

Yellow tea – No oxidation

Pu-erh – fermented (sheng pu-erh is not oxidised but shou pu-erh is)

Caffeine

I was reading an old article from Bord Bia that said that tea consumption was on the rise at night-time. The reason given was that “people are at home more often and tea is a comforting affordable reliable beverage”.

There have been several papers written on the effect of caffeine on sleep disruption and even more papers written on effect of caffeine on other health issues (good and bad). A major problem in this type of research is that all the papers tend to use very different values for the caffeine content in beverages and foods.

There are plenty of reasons for the variations. Preparation plays a large role and differences in the time and temperature of steeping, the size of the tea leaf and the type of tea used will all influence the caffeine content of tea. The variety of plant, care of the plants, soil nutrients, picking season and the part of plant used will also play a role.

Caffeine Crystals under the microscope

Caffeine Crystals under the microscope (Source)

Caffeine is a white, odourless crystal that occurs naturally in coffee, tea and chocolate and is added to colas and energy drinks. After a lot of reading, here is a summary of caffeine content in tea from sources that seems reliable:

Tea (~200ml after one steeping of three minutes)

Chinese white tea – 75mg

Darjeeling white – 56mg

Indian Green – 59mg

Kenyan Green – 58 mg

Chinese Oolong (Ti Kwan Yin) – 37mg

Assam (FTGFOP) – 86mg

Darjeeling Black (SFTGFOP1) – 54mg

 

For comparison here are some for coffee and other beverages:

Coffee (~200ml)

Coffee (ground roasted) – 115mg

Coffee (instant) – 80mg

Cola – 20mg

Decaffeinated coffee – 4mg

Espresso, single shot – 75mg

Espresso, double shot – 150mg

Red Bull (250ml can) – 80mg

 

Chocolate

It seems to be generally accepted that there are 6mg of caffeine per 30g serving. But it seems to vary a lot:

70% Green and Black dark Chocolate (30g) – 4.5mg

Green and Black milk chocolate (30g) – 2mg

White chocolate (30g) – 0mg

Cadbury dairy milk (28g) – 15mg

Herbal tea

Herbal tea – 0mg

(Note: other substances like theobromine, tanninic acid, caffeol also play a role)

 

I found it surprising how high the caffeine content of green tea is. Many claim that green and white tea have less caffeine than oolong or black tea because of the minimal oxidation. It seems to be well-proven now that this is not the case. White tea in particular uses the bud of the plant which has been shown to have a higher caffeine content that the leaf. I guess most people wouldn’t have a can of coke before bed but I wonder if they know that a Chinese white tea has three times as much caffeine?

With a few exceptions, herbal tea or tisanes have no caffeine at all. That includes Rooibos so there is a huge selection of tea alternatives for night-time. I’ve been going through a rough time with sleep lately so now I only drink tea up to about 3pm and right before bed I drink hops tea. It seems to really help. And no, by hops tea I don’t mean beer though sometimes that helps too :-).

 

Main Sources:

Barone JJ, Roberts, H.R. (1996), Caffeine consumption, Food and Chemical Toxicology, Volume 34, Issue 1, January 1996, Pages 119–129.

Richardson, B. (2009), De-bunking the At-Home Decaffeination Myth Story, Fresh Cup January 2009

Chin JM, Merves ML, Goldberger BA, Sampson-Cone A, Cone EJ. (2008), Caffeine content of brewed teas. J Anal Toxicol. 2008 Oct;32(8):702-4.