How and where to dry and store medicinal plants?

How and where to dry and store medicinal plants?

Drying is a method of preserving plants by optimal dehydration. Methods of drying medicinal plant materials are divided into two groups: drying with natural heat, without artificial impact (air-shade, solar) and artificial heating (thermal).

Solar drying, i.e. which is carried out using the heat of the sun’s rays, is the simplest, most economical and affordable method. It is used without harm to the roots, rhizomes and bark.

Air-shadow drying is carried out in the shade with good ventilation, in attics, where direct sunlight does not fall. The main requirements are maximum heat absorption of sunlight and good ventilation. Drying areas are usually equipped with canvas racks or metal mesh. 

The leaves turn brown after sun drying and the color of many flowers changes. Although these changes are not always accompanied by the decomposition of active substances, the appearance of raw materials deteriorates, therefore, the leaves and flowers should be dried only by air-shade method.

Raw materials containing essential oils are dried at a temperature of 30-45 ͦ C, spreading a layer of 10-15 cm to prevent evaporation of active principles..

Plants with an intense aroma must be dried separately from others.

Raw materials containing ascorbic acid are dried quickly at a temperature of 80-90 C.

It was established that in the roots of barberry and hawthorn fruits the content of active substances is higher if they are dried at a temperature 80-90 C.

In autumn, when it is not possible to dry the plants outside and provide thermal drying, ovens are used. Commonly rose hips and other juicy berries are dried in such a way.

Immediately after the furnace is heated, medicinal raw materials cannot be put in it: a two-three-hour break is necessary. In order to check, a thin paper is placed inside the oven – if it does not catch fire, the raw material can be brought in.

For the best use of volume of the furnace two-and three-level racks made from plywood sheets or a metal grid can be applied. If the raw material does not dry within the first time, it is carefully removed from the oven, placed in a dry place and the next day the process is repeated.  

BUDS of the plants are dried quickly at a moderate temperature (25-30 °C), spreaded in a thin layer, stirred often to prevent mold.     

Bark is usually dried outdoors or in a well-ventilated room. The bark is laid out on the underlay in a thin layer, turned over from time to time, but its pieces should not fall on top of each other.

When its drying on the air, as well as at night, to remain protected from dew and rain, it should be brought into the room.The bark almost always darkens, when its dried, and becomes of a brownish color.

Properly dried bark is broken with a crack, not bending.

The leaves are dried in the fresh air in the shade or in a well-ventilated room, in attics under an iron roof, spreading in 2-3 layers. Large leaves should be laid out alone.

In all cases, the leaves are spread in a thin layer. If necessary, they are  cut off the petiole.

FLOWERS must be dried at the day of collection on the  fresh air in the shade or in a well-ventilated room. They are laid out on the underlay, gauze or paper in such a thin layer that they do not have to be mixed.

Firstly, peduncles, stalks, sepals are removed from the flower mass. It is necessary to make sure that the flowers are not dry out, retain their natural color.

FRUITS, BERRIES, SEEDS are dried immediately after harvesting with access to the fresh air: in attics under an iron roof, in a heated oven, spreading a thin layer on dryers – covered with cloth or gauze, frames, sieves, iron or plywood sheets, etc. Rose hips must be dried first under the sun (this significantly speeds up the process of further drying and prevents the appearance of lumps). During drying, the fruits and berries should be carefully mixed, making sure that they are not sticking together or drying out. Juicy fruits are dried in ovens so that during storage they are not sticking in lumps. 

UNDERGROUND ORGANS (roots, rhizomes) are first cleaned of soil, dead and excess parts, then washed and dried in a warm room, attic, and other well-ventilated places (at a temperature not exceeding 35-40 C), spread on thin underlay layer and stirring often. Before drying the roots and rhizomes are recommended to be  dried for 1-2 days in the fresh air, in the shade. Thin and chopped thick underground organs require less drying time. 

The raw materials are packaged after drying mainly in bag containers. To prevent medicinal plants from losing their properties, they are stored in special conditions: in a clean, dry, well-ventilated room that is not exposed to direct sunlight and moisture. Berries should be stored in constant drafts (preferably by hanging in cloth bags).

Each package of medicinal raw materials must have a label indicating the type of raw material and the date of collection.

Raw materials are stored in small quantities in closed plywood or cardboard boxes, airing them from time to time.