The Science of Saffron Drying: don’t waste your money
Author : Hamed Biglari | 2024 Jan 25

The Science Of Saffron Drying: Don’T Waste Your Money

If the saffron stigmas were dried inaccurately after separating from their petals, they are worthless and have low quality. So don't waste your money because it is worthless same as a wheat straw. The dried stigmas of Crocus sativus L., a perennial crop in the iridaceous family that blooms in the middle fall are well known as Saffron.

Saffron is one of the most expensive incomparable spices in the world of human food industries. Saffron has been used as a unique unbeatable flavor and aroma to food and beverages, manufactured medicines and edible dyes, and even dyeing wool fibers and coloring paintings from many years ago. The history of using Saffron goes back to the early ancient times. The use of Saffron is prevalent in Iran, North Africa, Africa, and the Indian subcontinent. This famous spice tastes slightly bitter and has a sweet aroma. Preserving the health benefits of this valuable spice is highly dependent on its overall quality of planting, processing, harvesting, enclosing, and finally, how to use it correctly. The quality of an agricultural product is determined and defined by the precision and delicacy of performing these five essential stages of product processing. In 2015, the World Organization named its slogan Food Safety from Farm to the Mouth. The set of these factors in the form of the HACCP standard expresses the direction of risk analysis and crisis control in the food industry as a part of the food process steps developed by the Codex Food Committee, a subgroup of the World Health Organization (WHO). After picking the saffron flower, due to its delicacy and rapid spoilage, the saffron filaments (red stigmas) quickly separate and dried.

What is the effect of Saffron drying methods on their quality?

At least 28 distinct compounds in saffron influence the spice's color, flavor, and aroma. The primary bioactive substances in stigmas are Crocin (coloring material), Picrocrocin (Taste Material), and safranal (Odor material), the concentration of which determines the quality of Saffron. Crocin mainly determines the final product's color, while the concentrations of Picrocrocin and safranal influence its flavor and scent. The quality of Saffron is heavily influenced by its origin, climate, farming practices, and post-harvest processing (drying, storing, etc.). To produce Saffron of superior grade, stigmas must be sufficiently dried to remove more than 80% of their water content. Studies have revealed how the drying process affects the quality of Saffron. Saffron has to be dried to stay fresh while being stored. Nonetheless, accurate drying is necessary to get flavorful and vibrant Saffron. In addition, improper drying and storage methods have led to a decline in the stigma of Saffron's productive components and nutritional value, diminishing its export worth and reputation.

Why should Saffron be dried?

The drying stage is one of the most important and best stages of processing this expensive and fragrant spice. Suppose the Saffron has moisture and has not dried correctly. In that case, the saffron stigmas (saffron stigmas) are not easily powdered due to their high moisture content, and in addition to the fact that you have paid more for the weight due to moisture at the time of purchase, in this way, the period of Its storage time is also very short. It cannot be kept in a closed container. Drying Saffron can be stored for three years or more with the slightest change in color and aroma and maintains its quality well.

Does the quality of saffron change over time?

Since the temperature of drying and storage of saffron stigmas at the time of picking and cleaning is one of the most critical processes of principles of harvesting and storing genuine quality saffron, the following, the most important traditional and industrial methods of drying Saffron are explained. In ancient, simple and basic methods were used to dry freshly picked saffron stigmas. Still, today, with the invention of large and small fruit and vegetable dryers, saffron Stigmas are usually no longer dried traditionally. In the conventional method, the drying time is longer; there is a possibility of the saffron strands becoming moldy, the slowness of the process causes the color of the saffron strands to darken, and also, if the Saffron is not placed in a clean cloth or left open during the day. There is a possibility of contamination of saffron stigmas with external factors such as dust. These issues have caused the desire to use home and industrial drying devices to increase, which is why many people believe that drying Saffron in a new way and using a device is more efficient than the traditional method. But in reality, do new methods preserve or improve the quality of Saffron? Nowadays, the drying of Saffron is generally done in two ways: home dryers and industrial or mechanized dryers. In the following, the method of drying Saffron in these methods has been investigated.

Drying Saffron at home (Old Method)

Some people may want to dry Saffron for home use alone, or if the amount of Saffron they produce is small, they can use home saffron dryers for this purpose. In this case, instructions for working with it are provided to use that home dryer, and following the instructions in total is recommended while reading the instructions. For this purpose, we place the saffron flat and thin on a flat surface in a dry and cool environment so that the moisture evaporates and the Saffron dries. In this method, Saffron is usually placed in a basket or similar container with a hole in the curtain and covered with a thin cloth. Then, these baskets are placed in a room with a favorable ambient temperature (27- 37 Centigrade) or hung from the ceiling, and every few days, the bunches of Saffron are turned upside down so that all the strands become the same. The most crucial point in drying Saffron at home is avoiding direct contact with sunlight. Therefore, you can use shades or an environment protected from direct sunlight. Also, if possible, you can use the mild temperature of the ventilator or a fan to speed up the drying time.

Drying Saffron by mechanized or industrial method

To dry Saffron on a large scale, other household dryers do not have insufficient power, and an industrial dryer must be used. Industrial dryers are more professional and significant than domestic ones and can dry more Saffron at each stage. This method is suitable for commercial and commercial mass production of Saffron. First, the saffron stigmas are separated from their petals, and then the saffron stigmas are placed in a clean and dry cloth, usually made of cotton or silk lace (natural fabric). They adjust the dryer. Setting the time in drying devices is different according to the type and model of the device. Still, setting the temperature between 40 and 50 degrees centigrade and the time between 2 and 3 hours is recommended. In the Spanish method, the temperature of the saffron dryer is set at 75 degrees centigrade to dry the Saffron in a shorter time (15 to 20 minutes). We do not recommend this in any way because, according to scientific books and laboratory results, valuable organic and volatile substances found in medicinal plants and spices such as Saffron evaporate or change shape at more than 40 degrees centigrade, and They disappear. Therefore, it is suggested to set the temperature of the process to a maximum of 40 degrees Celsius and check the Saffron stigmas regularly for 2 to 3 hours during the drying process. When the saffron strands become brittle and can be ground well, it is time to finish drying. The moisture content of saffron strands that have been dried properly is about 4-5%. In some cases, as a fraud, the humidity of saffron strands is set to about 10-12%, which may cause it to mold after packaging in a high possibility. The first and most important reason for using dryers is their high capacity, power, and time-saving. In this method, the final quality of the product, in addition to the type of device that has a variety of heating technologies, is highly dependent on the setting of temperature parameters and the time of using closed or open hot air circulation systems in saffron dryers. Finally, after the end of the work, the dried saffron machine is completely cooled. In hygienic and primary conditions, the Saffron is packed in containers of different materials according to the customer's order and sold in the market. Sometimes, in many centers, Saffron is kept open for a long time in large containers without packaging, which causes secondary pollution; in addition, exposure to light and ambient temperature reduces the amount of coloring and the taste and aroma of this expensive spice. Are valued. The following two examples explain the best examples of industrial Saffron drying machines.

The Dandan Chen et al. study which is a complete study related to this subject titled “Effects of different drying methods on appearance, microstructure, bioactive compounds and aroma compounds of saffron (Crocus sativus L.)," examines various methods of drying saffron stigmas, including vacuum drying (VD), microwave drying (MD), oven drying (OD), infrared drying (ID), and freeze-drying (FD). In terms of appearance, color, microstructure, bioactive chemicals, and fragrance components, the quality of the dried samples was compared. According to their findings, the drying process had a major impact on the saffron's color, morphological traits, bioactive makeup, and scent. Of the five procedures, freeze-drying took the longest time to dry, while infrared drying took the shortest. Low-temperature freeze drying produced the greatest. Of the five procedures, freeze-drying took the longest time to dry, while infrared drying took the shortest. Of the five techniques, low-temperature freeze-drying produced the saffron with the greatest color values. Of the five drying techniques, the freeze-drying sample retained its original cellular structure and grain features with just a little cell shrinkage, according to an SEM study of dried saffron. Using samples that were freeze-dried and microwave-dried, HPLC measured Crocin I and Crocin II while preserving the majority of total Crocin. The scent components of saffron dried using the five ways were identified and quantified by GC-MS; samples dried using infrared and microwave technology retained the highest concentration of aroma compounds. However, microwave drying could be the best technique for maintaining a higher amount of crocin and fragrance components, and MD time is relatively short, given the high cost and energy consumption of freeze drying and infrared drying. According to this study, the best drying techniques for preserving bioactive or fragrance components were FD, ID, and MD. While ID resulted in the quickest drying time (0.7 h), FD maintained its good appearance color, whole initial cell structure, and intact pollen grains. But FD duration was the longest (47 hours); FD's expense and energy use. Therefore, considering energy consumption and the quality of saffron, MD might be the most suitable method for both keeping the content of Crocins and aroma components, and its drying time was short (1.9 h).


What is freeze drying of Saffron?

In the freeze-drying method, the product is first placed at -22 to -18°C for 20 hours and then set at a temperature of -13 °C and a pressure of 0.15 mmHg for 12 hours. In this way, the product's Crocin pigment is very high. It should also be noted that the color of the obtained saffron will be red-orange, which is undesirable due to consumers' insufficient mentality towards the redness of saffron.


Saffron dryers with warm air circulation

Hot air comes into direct contact with the product in warm air dryers (Basically, a suitable device provides heat through either microwaves or warm water flow). The most important of them are tunnel dryers. In this method, the Saffron quickly loses 50% of its moisture by passing warm air over the Saffron Stigmas or Saffron passing through a thermal tunnel. Then, it is separated using wind power based on the difference in volumetric mass and by passing through an electrical device. There are other types of dryers, such as vacuum dryers, sieve and heater methods, and solar dryers, all of which are classified in the group of thermal dryers.

What are the best containers for packing Saffron?

How to keep Saffron?

In the usual industrial drying method, no pressure is applied to the saffron strands, which are not compressed. In some mechanized models, Nagin-type saffron is placed under the pressure of a metal piece (like an iron); this action causes the strands to become broader and smoother; in this case, they are called Super Nagin-type saffron. Naturally, due to the higher heat given to the surface of the saffron strands, the quality of this type of Saffron (super precious Saffron) is lower than the type of precious Saffron or the local term "Sargol saffron." Still, due to the appearance of the strands, they are more extensive and more beautiful. They are sold fresh and dried at a higher price than other types of Saffron. The literature reports three primary temperature ranges for dehydration: low (room or air temperature), mild or medium, and high. Using high, medium, and low temperatures, Spanish researchers examined the effects of various drying techniques on the Saffron that was cultivated nearby (Manuel et al., 2005). They assessed the moisture content, fragrance, bitterness, and color depth. Compared to samples dried at 194 °F [90 °C] and 230 °F [110 °C], the Saffron dried at ambient temperature had a much worse quality (i.e., color, taste, and scent) and a more excellent moisture content.

What are the types of Saffron?

How do we recognize that industrial or old methods have dried Saffron?

Considering the color of dried saffron strands, this can be understood almost. The evaluation results have shown that dried Saffron with dryers has a bright red color and a more pleasant aroma. While the color of dried Saffron in the traditional method is dark red, the curling in the strands is much higher than in the mechanized method due to the slow drying speed.


Many studies have reported that fragrances and volatile substances in herbs, considered valuable food substances, burn or evaporate at temperatures higher than 40 degrees centigrade. On the other hand, many results papers and our laboratory research revealed carbon materials are deformed and destroyed at more than 40 degrees. Therefore, despite all the results suggesting high temperatures for drying Saffron and may be biased, using natural and low temperatures in a sanitary environment is very suitable. 

The simple and best way to dry saffron stigmas is if you have a suitable and hygienic space, dry it in the shade and dry environment with an ambient temperature of between 30 to 40 degrees centigrade. The saffron stigmas dried by the traditional method are of much higher quality than those dried using unprofessional industrial methods. Some advanced industrial methods that simulate traditional processes, such as tunnel dryers with a dry and slightly warm air flow cycle, are also helpful. Don't forget that freshly dried saffron is much higher quality than saffrons, which have been stored for a long time in common conditions. some enclose technology using the injecting of nitrogen gas and carbon dioxide to remove oxygen gas and moisture in packaging has provided a good idea to increase the shelf life of their products.

Since detecting these issues is not easy, we at Flonita Saffron company monitor all own products by knowledge, and skilled experience in all process steps. we always try to use methods of old and new sciences while using understanding and research. You could check our facts sheet results, with genuine quality saffron without exaggeration and advertising based on the presentation of quality laboratory documentation. Here you can buy the quality saffron by comparing the product's quality results with confidence. We guarantee all our products with confidence. In case of dissatisfaction and incompatibility of products with the laboratory results of any product, we guarantee the definitive return of your money indubitable.

Chen D, Xing B, Yi H, Li Y, Zheng B, Wang Y, Shao Q. Effects of different drying methods on appearance, microstructure, bioactive compounds and aroma compounds of saffron (Crocus sativus L.). LWT. 2020 Feb 1;120:108913.


Hamed Biglari

Assistant Professor of Environmental Health Engineering in Gonabad University of Medical Sciences, Razavi Khorasan, Iran

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