Pǔ’ěr chá storage (in Western Europe)

1.1 No light

Choose a location with neither direct nor indirect sunlight (= ultraviolet radiation) exposure:

• direct sunlight damages organic material (“bleeching”)

• indirect sunlight by heating up the containers inbalances the microclimate (“suppression”)

1.2 No odors

Choose a location with neither direct nor indirect odor exposure:

• direct odor immissions (like incense, food, air polution, etc.) makes the tea undrinkable

• indirect odor immissions (especially other teas stored next to it) taint the taste and dilute the flavours

Always use individual containers for each tea, store only identical tea of the same year and batch in the same container. Idealy never store one cake, brick or tuo on its own, buy multiples and store them together for better ageing.

2.1 Consistent temperature

Use a location with no interference from any devices or structures next to it:

• use an regular indoor location for mild temperature curves (i.e. no attics with large day/night temperature differences)

• aim for >= 20°C average temperature for natural storage (i.e. no cold basements)

• don’t use a place next to any heat dissipating devices (like radiators, computers, etc.)

• don’t use a place next to an outside facing wall

• always leave 5 to 10cm distance to a wall for air to circulate (generally prevents mold on the wall but also isolates the containers further from possible immissions)

As consistent temperature as possible allows even and steady fermentation. However, neither air conditioning or filtering is needed. Regular day to day, day to night, and season to season fluctuations are balanced out fine with otherwise correct indoor storage. Also humidity control is much more important for storage and ageing, and much less forgiving than temperature control.

2.2 Consistent humidity

Use humidity control packs to ensure a stable humidity level:

• aim for ~65% RH

Lower than 60% RH will (completely) dry out the tea, higher than 70% RH increases chances for mold.

3.1 Proper containers

Use containers that are long term available and that are easily stackable, both in form and dimensions as well as load-bearing capacity. They should be inexpensive, otherwise it’s most likely scam (there are people selling snake-oil containers “specifically” for tea storage).

For long term storage and ageing:

• never use plastic: they leak chemicals over time (no “tupperdors”, mylar and zip lock bags, etc.)

• never use cardboard or bamboo: they let to much air in, absorb too much humity and dry to slow

• never use wood: they emit odors (no humidors)

• never use clay: they absorb all humidity and dry out the tea (glazed or porcelain urns are acceptable for short term storage)

Always use sealed but not air tight, cleaned steal cans (i.e. with no oil residues from manufacturing; such as these).

3.2 Proper humidity control

Use two-way humidity control packs to either absorb or add moisture depending on the needs:

• use humidity control pack(s) in every container

• use one 60g pack (such as these) per 500g of tea

3.3 Proper labels

Put labels on the outside of the containers to not need to open them to know what is inside and disturbe the ageing:

• write at least manufacturer and name, pressing year, and batch number on the label (such as these)

• if desired and not otherwise kept track already elsewhere, add additional information such as the amount of items, weights, previous storage location/type, date of purchase, vendor, or price, etc.

3.4 Proper monitoring

Measuring and checking temperature and humidity regularly prevents storage parameters turning bad going unnoticed:

• put temperature and humidity measurement sensors (such as these) inside some of the containers (e.g. at least one in every different size/type of container)

• keep at least one temperature and humidity measurement sensor next to the containers on the outside to monitor the storage location

4.1 Continued maintenance

Before beginning to initially store a new tea, let it acclimatize for 2h after unpacking from transport (or longer if temperature differences between indoors and outdoors are high, i.e. in winter).

Then continuesly:

• once a month briefly air all containers for a minute or two

• once a month check for mold, just to be safe

• every 3 to 6 months check all humidity control packs for need of replacement

• monitor battery life of temperature and humidity measurement sensors

Humidity control packs can be recharged (usually voiding any warranty) by submerging them for 2 days in distilled water and 4 hours drying on paper towl afterwards. Check with a weight scale after recharging, they should regain their original weight (e.g. 60g plus ~2 to 5g for the packaging).