TEA 茶

南投縣是台灣茶葉種植面積最大，產量最多的地區，特別能展現台灣茶多元的樣貌，魚池鄉特別能展現今日台灣紅茶的地方。魚池鄉發展紅茶的歷史可以追溯到日治時期，當時日本人引進阿薩姆茶種種植，並在日月潭附近進行育種與製茶試驗。在日治時期的台灣紅茶外銷，多還是從台北至新竹與苗栗一帶的茶廠生產，到了二戰後國民政府紅茶外銷的鼎盛時期，中部產區的紅茶產量也持續攀升，魚池鄉當然也成為產製紅茶的主力地區，而我們今天所介紹的日月老茶廠就是在該時代下的產物。

日月老茶廠的外部場區介紹

日月老茶廠距離日月潭風景區不遠，是南投魚池鄉茶文化重要歷史建物之一，日月老茶廠目前還保留原建築結構，但有稍微整修部分的內部空間，轉型為具茶葉生產、販售、飲食、活動等複合功能的場址。日月老茶廠設立於1959年(民國48年)，建廠後專注於紅茶的製造，在茶廠的二樓仍保留4座大型紅茶萎凋槽，但拆除了傳統的紅茶萎凋架，萎凋空間利用特殊的窗戶環境自然通氣，另外利用萎凋槽通氣強制對流方式，促進紅茶萎凋速度；茶廠的一樓仍保留數台老舊的傑克遜式茶葉揉捻機、解塊機、篩分機、甲種乾燥機、以及紅茶發酵室與茶葉精製室。日月茶廠內部的製茶機具現在仍持續有在運作中，如果有幸在製作紅茶的季節參觀茶廠，或許能一覽整個紅茶製造的流程。

進入日月老茶廠的道路兩側有種植一些茶樹，除了小葉種的茶樹，還有日月潭地區大量種植的台茶18號紅玉。以日月老茶廠周圍的茶園面積來說不足供應大量茶菁原料，在日月老茶廠附近應該還有其他農林公司的茶園供應製作紅茶的原料。日月老茶廠建築的牆壁上有藤蔓植物-爬牆虎，攀附在米白色的牆上，有綠葉又有些轉為紅黃色非，配上藍色的窗櫺又更詩情畫意，感覺不像是個製茶工廠。

日月老茶廠內的場區

現在參觀老茶廠除了古樸絕美的環境外，我們也可以從茶廠的區域配置，一覽紅茶製造的過程，尤其日月老茶廠還有持續進行紅茶的製造，更能感受到這個茶廠的活力。首先依據紅茶的製程，一開始需從茶廠外將採收的茶菁運進廠內，接著進行長時間的萎凋，萎凋至一定程度後再進行揉捻，揉捻的過程中還需將緊節的茶球解塊，揉捻至一定程度後接著就會開始進行發酵，待發酵完成即可進行烘乾，再進行茶葉的撿梗與精製。而茶廠內的動線也依據紅茶的製程安排，一開始大量的茶菁會利用輸送帶將至運送到茶廠二樓進行萎凋。

萎凋結束後會將茶葉送茶廠二樓送往一樓進行揉捻，為了避免搬運大量茶菁，萎凋空間的地板有開設方型的輸送口，可以將茶菁直接從輸送口投入下方的茶葉揉捻機中，即可快速進行茶葉的揉捻。

What's the carbon footprint of brewing a cup of tea?

You might think that tea is just an agricultural product and probably doesn't have much carbon emissions, perhaps only from the machinery used in tea processing or the slight carbon emissions from burning gas when boiling water for tea. However, the carbon footprint of tea is more complex than you might imagine.

To understand the carbon footprint of tea, one must grasp the concept of "product carbon footprint life cycle". Firstly, although it's called a "carbon" footprint, it actually includes emissions of various greenhouse gases, not just carbon dioxide. Different greenhouse gases have different Global Warming Potentials (GWP). This can be understood as their ability to cause the greenhouse effect compared to carbon dioxide. For example, methane (CH4) has a GWP value of about 28, meaning that emitting 1 kg of methane is equivalent to the greenhouse effect caused by 28 kg of carbon dioxide (CO2). In other words, emitting 1 kg of methane equals 28 kg of carbon dioxide equivalent (CO2e). Finally, the impact of all greenhouse gases is expressed in terms of carbon dioxide equivalent (CO2e).

Additionally, we need to understand the concept of a product's "life cycle". First, we must determine which stages need to be calculated in this cycle, what relevant emissions need to be calculated in these stages, and which emissions can be excluded. In Taiwan, the carbon footprint life cycle of tea products includes cradle-to-grave, which means from tea tree planting to the disposal of tea waste. Why is it called a cradle? You can think of it as a newborn baby sleeping in a cradle. For products, it refers to the raw materials needed for production. The raw material for tea making is simply the tea leaves harvested from tea trees. The tea tree might initially be a seed or a cutting, and we also need to include emissions from fertilizers and materials used in tea garden management. The grave, as you might guess, is the endpoint of the product. Just as humans are buried in coffins and then in graves after death, products will eventually become waste. For tea products, besides packaging waste, the used tea leaves from brewing also generate carbon emissions during waste treatment. The disposal of tea product waste is the endpoint.

Cradle-to-Grave: From tea seedling growth to tea waste disposal.

Cradle: Refers to the starting point of raw materials. Why use a cradle? It's like a newborn baby sleeping in a cradle. Producing a product requires raw materials. The raw material for tea making is simply the fresh tea leaves harvested from tea trees, which come from tea gardens. The tea tree initially might be a seed or a cutting.

Grave: Refers to the endpoint of the product. Compared to the cradle? After death, people lie in coffins and are then buried in graves. The used tea leaves after brewing, the process of disposing of tea leaves may also generate carbon emissions. When the tea product is discarded and finally disappears, that's the endpoint.

The cradle-to-grave product carbon footprint life cycle is the most complete. The cradle is just the starting point, and there are many greenhouse gas emission activities in the subsequent processes. For example, after the tea seedlings grow, various tea garden management activities are needed. During this period, there are emissions from the burning of agricultural machinery, nitrous oxide (N2O) emissions from fertilizer application, or electricity use of equipment in tea factories and gas use in drum-type roasting machines during the tea-making stage. Additionally, it extends to the packaging and transportation of tea products, to consumers boiling water to brew tea, and finally to the disposal of used tea leaves, which completes the full life cycle. In short, from planting tea trees to disposing of used tea leaves, all related carbon emissions are included in the tea product's carbon footprint life cycle, but some items can actually be excluded.

Cradle-to-Gate: From tea seedling growth to tea leaf harvesting in the garden, or from tea seedling growth to the output of tea products in the tea factory.

Gate: Refers to the cut-off point for emissions. For the tea industry, cradle-to-gate could be the tea garden or the tea factory. If it's a contracted tea garden, fresh tea leaves are a product, so cradle-to-gate would be the process (and emissions) from planting tea seedlings to harvesting fresh tea leaves in the garden. If it's a tea farmer who both grows tea and processes it, then cradle-to-gate would be from planting tea seedlings, through the tea-making process, and even to packaging it into a tea product.

For the tea industry, cradle-to-gate could refer to either tea plantations or tea processing factories. If it's a contract tea plantation, tea leaves are considered a commodity, so cradle-to-gate refers to the emissions from planting tea seedlings to harvesting tea leaves in the plantation. If it's a tea farmer who both grows tea and processes it, then cradle-to-gate encompasses everything from planting tea seedlings through the tea processing stages, and may even include packaging the finished tea products.

Gate-to-Gate

This can be understood as a process occurring within an independent tea factory, from when raw materials are delivered through the factory gates until the finished products are transported out of the factory gates. The tea factory purchases fresh tea leaves (raw materials) from contracted tea farmers, produces finished or semi-finished products (goods) through tea processing operations. Finished products are packaged within the tea factory, while semi-finished products such as roughly processed tea still need to be sent elsewhere for stem removal or color sorting for refinement.

How are the stages of carbon footprint divided in Taiwan's tea industry?

The carbon footprint of Taiwanese tea products includes various greenhouse gas emissions from cradle to grave. However, how do we define which processes or stages need to be calculated for emissions? It is necessary to refer to the Carbon Footprint of Product-Product Category Rules (CFP-PCR) published by the Ministry of Environment. This document establishes a reference standard for similar product categories, defining the stages that generate carbon emissions and related assumptions. This article explains this based on the Ministry of Environment's Carbon Footprint of Product-Product Category Rules (CFP-PCR) for Tea, Version 4.0.

The Product Category Standard divides the life cycle scope of tea products into five stages:

Raw Material Acquisition: This includes carbon emissions from fertilizers, pesticides, consumables, and packaging materials used in tea leaf production; carbon emissions from energy resources used by agricultural machinery; transportation emissions from moving tea leaves from plantations to tea factories; and emissions from waste disposal.

Processing: First is the rough processing of tea, referred to as "primary processing" in the product category rules. For semi-fermented tea, this includes withering, pan-firing, rolling, and drying. Carbon emissions calculated include electricity usage in the tea factory and liquid petroleum gas combustion in pan-firing machines and Type A and B drying machines. Next is the tea refining stage, called "secondary processing," which includes stem removal, cutting, sorting, roasting, and blending. Finally, there is tea "packaging," which includes electricity used by vacuum machines. Overall, manufacturing stage emissions mainly come from energy resources (fuel and electricity) used by factory machinery, as well as emissions from waste transportation and processing.

Distribution and Sales: This covers emissions from transporting tea products to sales locations, including vehicle emissions. There may be several warehouses involved, all of which need to be defined. As for calculating emissions until the product reaches consumers' hands, since consumers are distributed throughout Taiwan, it's difficult to calculate accurately. Therefore, calculations typically only include transportation emissions from the tea factory to main sales points. Additionally, transportation scenarios need to consider factors such as distance, mode of transport, loading rate, ton-kilometers, average fuel consumption/cost, etc.

Consumption: The tea carbon footprint product category rules estimate consumer usage emissions through scenario assumptions. The scenario assumes a ratio of 3g of tea to 150ml of hot water, calculating the energy required to heat room-temperature water to boiling using electricity, liquefied petroleum gas, or natural gas. Since it's difficult to estimate how consumers will use the tea (they might cold-brew it or use different tea-to-water ratios), a uniform standard is established for calculating carbon emissions during the tea usage stage

Disposal: This also uses scenario assumptions, calculating the carbon emissions from tea waste disposal based on Taiwan's published ratios for common waste treatment methods: 1) incineration and 2) food waste recycling.

However, there are many differences in how product carbon footprints are defined across the lifecycle. Research from mainland China also divides tea carbon footprints into five stages, but with some differences in terminology and stage differentiation (Figure 3). This research includes the stages: 1. Cultivation 2. Processing 3. Packaging & Transport 4. Consumption 5. Disposal.

In this case study, the manufacturing stage only includes the rough processing and refining of tea leaves without packaging. Instead, packaging and distribution are classified in the same stage, possibly because the local tea industry chain often sells roughly processed tea before proceeding with standardized packaging. In contrast, Taiwan's product category rules include packaging in the manufacturing stage. Although packaging activities represent a very small proportion of the overall tea carbon footprint, calculating them in different stages still results in slight differences.

Overall, calculating the carbon footprint of tea may seem simple, but it actually requires substantial data on tea garden management, tea processing, and even transportation to calculate the complete greenhouse gas emissions throughout the tea life cycle, which are then uniformly converted to carbon dioxide equivalents to represent the carbon footprint. After calculating the tea's carbon footprint, one typically seeks to obtain a carbon footprint label issued by the Ministry of Environment. For this purpose, carbon footprint verification must first be obtained. Applicants need to follow the aforementioned carbon footprint product category standards and ISO 14067:2018 standard to write a report on carbon footprint inventory, which must present all information about scenario assumptions, emission activities, and carbon footprint calculations, including emissions related to electricity, liquefied petroleum gas, packaging materials, fertilizers, etc., as well as emissions from distribution and sales, usage stage, and waste disposal stage scenario assumptions, ultimately calculating the emissions per unit of product. After a third-party verification agency conducts data verification and issues a verification statement, one can apply to the Ministry of Environment for a carbon footprint label for tea products.

Other questions about the carbon footprint of tea?

Q: Which stage of tea products has a higher proportion of carbon footprint?

The carbon footprint proportions vary depending on different countries' tea garden management, manufacturing methods, use and disposal scenario assumptions, carbon footprint coefficients for fuels and electricity, and differences in manufacturing stages for various tea types (such as black tea, green tea, partially fermented tea). Therefore, the stage with a higher carbon footprint proportion may differ by region and tea type.

Q: Do different tea consumption methods also create different carbon footprints?

Tea consumption methods indeed affect the carbon footprint. Most studies assume consumers use boiling hot water to brew tea leaves, but cold brewing would result in a different carbon footprint. Western research shows that black tea with milk has a higher carbon footprint, while in Taiwan, hand-shaken drinks with various ingredients would make calculations even more complex.

Q: Can't tea plantations absorb some carbon dioxide?

Tea plantations can absorb carbon dioxide from the atmosphere. Research on green tea from mainland China includes calculations of carbon sequestration by tea plantations, which can reduce overall carbon emissions and lower the carbon footprint per unit of product. However, calculating the exact carbon sequestration of tea plantations requires more rigorous methodology.

Q: Does a carbon footprint label add value to tea products?

The impact of carbon footprint labels on adding value to tea products is not straightforward. Different tea garden operations and tea factory models, as well as items excluded when calculating carbon footprints, can all lead to differences in the final tea carbon footprint. For example, high mountain tea may have a higher carbon footprint, mainly due to the long distance of material transportation and high emissions during the transportation stage. However, because of differences in calculation methods among various operators, it is inappropriate to judge the quality of tea products based solely on the carbon footprint. It's important to note that tea carbon footprints need to be verified by third-party verification agencies before applying for a carbon footprint label from the Ministry of Environment, which represents a significant cost for businesses.

歡迎聯繫TRIT討論