Humidification in Tea Production

Q: What is the ideal humidity level for tea oxidation / fermentation?

Maintaining a relative humidity of 95–98% at 20–26°C ensures optimal development of flavour compounds like theaflavins and thearubigins, which define the character of black teas.

Q: Why is humidity control important in tea production?

Humidity plays a critical role during the oxidation (fermentation) stage of tea processing. Maintaining a relative humidity of 95–98% at 20–26°C ensures optimal development of flavour compounds like theaflavins and thearubigins, which define the character of black teas, Pouchong, and Oolong.

Q: What happens if humidity levels drop during fermentation?

Even a small drop in humidity can slow oxidation and affect the quality of the final product. Dry leaves hinder the chemical reactions needed for flavour development.

Q: Is humidification necessary if the climate is naturally humid?

Yes. Even in humid climates, indoor conditions can vary. Condair systems provide reliable control regardless of outdoor weather, ensuring consistent production quality.

Q: What are the risks of using traditional spinning disc humidifiers in tea production?

Traditional spinning disc humidifiers often fail to distribute moisture evenly, leading to inconsistent fermentation, leaf discolouration, and reduced yield. Condair systems offer more uniform humidity control.

Q: What hygiene functions are required from a humidification system?

Humidification systems should be bacteria-free, capable of introducing moisture evenly across an area in a safe way. Any cold-water humidifier must incorporate automated flush and drain cycles to ensure water cannot remain in the pipework to stagnate, which could potentially create a health risk.

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Benefits

Correct humidity control during tea fermentation improves quality and has many benefits.

Enhanced flavour

Humidification during fermentation significantly enhances tea quality.

High ROI

Increased quality with higher market value.

Evaporative cooling

Low energy cooling to manage temperatures.

Tea production humidity control

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Higher quality tea whatever the outdoor conditions

Considered humidification and temperature control during fermentation (also known as oxidation) provides the right conditions for the polyphenols in withered leaves to develop into the theaflavins, thearugibins and other compounds that create the characteristic flavours and colour of black teas.

Consistent and accurate humidity across the fermentation room and within the CFM machine results in more moisture being retained within the leaf. If leaves dry, oxidation slows as water is required for the process. An ambient relative humidity of 95-98%RH is ideal to maintain optimal fermentation. This results in higher quality tea with a higher market value, resulting in rapid return on investment in the humidification system.

Humidity control in rolling rooms

Humidification of the rolling room and CTC area will prevent moisture loss from the tea prior to it arriving in the fermentation room. This will ensure the maximum amount of moisture is available inside the leaf to act as the catalyst for the oxidation process. A high humidity of around 90-95%RH will also prevent the leaf’s ruptured outer surface from sealing itself, which can inhibit the oxidation process. Although the tea spends a relatively short amount of time in this area, humidity control will still benefit the quality of the final product.

Humidity control in teabag production

For a factory producing tea bags, controlling the humidity to around 60%RH in the filling area will help reduce electrostatic build-up. Static can cause issues with tea bags sticking to each other and problems with filling, as tea won’t consistently flow. A dry atmosphere promotes static build-up and causes tea to stick and lump together, which can result in inaccurate volumes being introduced to each bag.

Evaporative cooling

Cold water humidifiers offer a low energy way to cool an atmosphere, as evaporating water provides 0.65kW of cooling per kg of evaporated moisture. Therefore, a spray humidifier delivering 100kg/h to a fermentation area is not only maintaining the humidity level but also providing 68kW per hour of evaporative air cooling.

When designing the fermentation area’s temperature control system, it is important to factor in this reduction in temperature from the humidity control system as escalating temperatures can impact tea quality. An even temperature across a whole area is required for maximum consistency and quality.

Use Cases for...

Prevent evaporative losses

Organic materials have an internal moisture content and will lose moisture to the atmosphere when exposed to air with a low humidity. Humidifiers are used to create an environment with perfect balance between the material’s internal moisture content and the air’s relative humidity.

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Projects and references

Parmeshwari Tea, India

Humidity control specialist, Condair, and its Indian distributor, Regent Machine & Servicing, has supplied and installed a JetSpray humidification system at Parmeshwari Tea factory in Assam. The compressed air and water spray humidifier is maintaining the ideal humidity in the CTC and CFM areas to prevent moisture loss from the tea during processing and fermentation. This results in a consistently high quality tea, which is blacker and with stronger liquor, no matter what the ambient weather conditions are like.

Sumonibarie Tea Factory

Together with our partner Regent Machine Servicing, Condair's JetSpray humidification systems have been installed at the Sumonibarie Tea Factory in Assam, India. Tea production requires carefully controlled environments to ensure the quality of the tea. The JetSpray systems are located in both the CTC room (Crush, tear, curl - a process to enhance flavour), as well as the fermentation room. Thanks to these systems, humidity is controlled to 80%-85%RH in the CTC area, and 90%-95%RH in the fermentation area.

Bajrang Tea, India

JetSpray humidifiers from Condair are maintaining an optimum 95% relative humidity (%RH) above the continuous fermentation machines at Bajrang Tea factory in West Bengal, maximising the quality of the tea produced there. The improved humidity control has resulted in enhanced fermentation of the tea with better infusion and liquor, and ultimately a higher market value.

Sabuj Agro Tea Factory, Bangladesh

The Sabuj Agro tea factory in Bangladesh has installed a Condair JetSpray humidification system to maintain the perfect humidity in its production facility and ensure the highest quality black tea.

By maintaining 95%RH in the factory, moisture loss from the cut leaves is significantly reduced. This improves the fermentation process, resulting in a more flavoursome tea with greater market value.

Southern Tea

Bogoda Tea Factory

The Bogoda Tea Factory is located in the Southern Province of Sri Lanka in Matara. Condair humidifies the tea production area.

Evergreen Tea Factory

The Evergreen Tea factory group is renowned for the production of best quality low grown tea. The present overall manufacturing capacity of the group exceeds 6,500 kg of green leaf per day and the annual tea production of 2.5M kg of made tea. A JetSpray humidification system from Condair is helping Evergreen Tea Factory maintain an ideal air humidity for optimum tea productivity.

Gunawardena Tea Factory

Gunawardana tea products have been established since 1991. The tea factory produces low country grown tea producing a monthly volume between 8000 - 10 000 kg. A JetSpray humidification system from Condair is helping the Gunawardena company maintain the ideal production environment.

Lumbini Tea Factory

The Lumbini Estate and factory was started by Mr. Dayapala Jayawardane in 1984. It is located in the mountainous village of Pallegama in southern Sri Lanka. Mr. Jayawardane named the estate Lumbini in honor of the birthplace of The Buddha. The factory produces almost exclusively black tea at approximately 600,000kg per year. The company employs 80 machine operators and 30 tea pluckers.A JetSpray humidification system from Condair is helping to maintain the ideal humidity in the Lumbini factory's fermentation area to promote optimum tea oxidation, improving liquor and blackness of tea, ultimately enhancing its market value.

Peak View Tea Factory

The Peak View Tea factory is part of the K.D.U. Group, one of the leading and largest tea manufacturers in Sri Lanka.

Uruwala Tea Factory

The Uruwala Tea Factory utilizes between 15,000 to 20,000 kilo grams of raw leaves each day and sends 65,000 to 70,000 Kilo grams of final tea product to the Colombo tea Auction. Raw tea leaves are brought to the factory from the surrounding small holdings up to 50km away. The Uruwala Tea Factory is a vital support to the local economy who depend on the factory for their income.A JetSpray humidification system from Condair is helping to maintain the ideal humidity in Uruwala's fermentation area to improve the density and liquor of the tea being produced for improved productivity and value at auction.

Quotes from our customers

Darshananand Holdings Pvt Ltd (Bajrang Tea Factory)Aditya AgarwalDirector

“Before we had the JetSpray humidifier, we were unable to achieve the high humidity levels we needed. Our previous humidification system also tended to cause wet patches on the floor nearby. However, since we had the JetSpray humidifier installed, the area is consistently at 95%RH and we’ve managed to virtually eliminate weight loss from the tea during fermentation. This means the moisture stays in the leaf, improving the tea’s fermentation and enhancing the quality of our finished product. We’ve found the JetSpray humidifier very easy to operate and the use of compressed air in the aerosol ensures we never get any drips from the nozzles or wetting on the floor."

Parmeshwari Tea CompanyAjay DhandhariaManaging Partner

"After installing the JetSpray system we observed that any level of humidity required is constantly achievable without condensation or water getting deposited on the floor or over the machine. With improved humidity conditions, teas became brighter, blacker with better bloom and improved density."

Frequently asked questions

What is the ideal humidity level for tea oxidation / fermentation?

Why is humidity control important in tea production?

What happens if humidity levels drop during fermentation?

Is humidification necessary if the climate is naturally humid?

What are the risks of using traditional spinning disc humidifiers in tea production?

What hygiene functions are required from a humidification system?

Free 10-point guide to improving tea fermentation with humidification

Download our free 10-Point Guide to Tea Fermentation and discover how precise humidity control can help optimise fermentation, improve consistency and enhance tea quality. Packed with practical insights and expert guidance, this easy-to-read resource highlights the key factors that influence successful tea fermentation and how to achieve reliable results batch after batch. Get your copy today and take the guesswork out of tea processing.

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