Cold chain in flowers or The Land of Degree Hours

DE KWAKEL, Netherlands: Dutch-based flower exporter Holex Flower BV teamed up with cold chain management guru FlowerWatch. Together they developed a KPI indicator, called ‘degree hour’. The protocol should reduce product waste and lead to return purchases.

Who doesn’t loves the crispy sound of fresh tulips, when you put them in a vase? The look of a perfect bridal bouquet, and knowing for sure that this will be the bride’s best day ever? The smell of lilac that’s put in the enormous centrepiece that you see when you enter your hotel lobby? Flowers nourish our senses. But only when they are in impeccable condition when we encounter them.

Getting flowers in perfect condition from nursery to consumer is a great challenge. During all stages, the people involved do their utmost best to maintain good product quality. But doing your best isn’t always enough. Why is it that some flowers are of poor quality, and others are shining in the vase for two weeks? When working with cold chain management expert FlowerWatch, Holex quickly found the answer: it largely depends on the degree hours.

Through their work with scientists and floriculture businesses, FlowerWatch has developed unique insights into the industry’s success factors. They have developed the ‘500 Degree Hour Norm’ quality assurance method which is central to their standards.

In this method, FlowerWatch uses the Celsius temperature scale. How it works? It describes the time-temperature exposure, which is expressed in degree hours. This is the average temperature of a given shipment of fresh flowers throughout transport, multiplied by the number of hours (1 degree hour = 1 hour x 1°C). Every 500 degree hours, from grower to consignee, reduces vase life by 1 day. The key to successful cold chain performance is to minimise the number of degree hours that a flower is exposed to, from the moment of cutting until it reaches the florist.

Holex customers, wholesale florists, are located all around the world. New York, Dubai, Seoul, Shanghai.. Just a few places where the Holex flower shipments arrive by plane every week. They travel thousands of kilometers to shine at the moment of need.

To be able to keep the Holex quality promise, that so many wholesale florists count on, Holex has undertaken a lot of actions to get more in control of the degree hours, according to the FlowerWatch Quality Standard.

In addition to the existing extensive precooling facilities, recently Holex has also had a vacuum cooler installed at their shipping department. This makes them the first flower exporting company in the Netherlands working inhouse with vacuum cooling techniques with flowers.

In cooperation with FlowerWatch, there have been developed practical procedures to make sure internally all FlowerWatch Quality Standard steps are taken: from arriving of flowers from the auctions or directly from growers, to storage, picking, and packing.

Next to this, Holex also has redesigned their complete range of flower shipping boxes. Sizes that match airplane skids perfectly, and makes sure that air circulation around the boxes is guaranteed so that air respiration of the flowers themselves cannot cause the flowers to heat up.

With these developments, Holex is able to reduce the degree hours in such a way, that they are at an appropriate level when the consignments leave the premises. Let’s give an example of how degree hours really make the difference.

It is Wednesday morning. The Holex buyers have received an order for Saturday arrival, and they are arranging the needed products at the Dutch growers. The products are transported to Holex, where they are stored in the cold room for 24 hours. On Thursday the products are picked and packed. After this, the boxes are brought to the Expedition cold room, where – for 24 hours – they are cooled down (at the vacuum cooler or the pre-cooling units) even more and will be put on airplane skids.

On Friday afternoon, the shipment is leaving the Holex facility and is transported to London Heathrow by truck, where it arrives Saturday morning. The airplane skids are loaded onto the plane, and in a few hours it will take off for a 9-hour flight to Miami airport, USA.

Due to time differences, the plane arrives at Miami Airport, USA on Saturday evening. The shipment goes through customs clearance, and after this, the shipment is brought to the freight agent. In Miami, Holex works with K&M Handling. In their warehouse, the shipment is cooled back to 2°C. On Sunday morning, the cooled shipment is ready for pick up by the wholesale florist or their trucker for the trip to its destination, the cash and carry store.

During this long-haul trip it is crucial to look at the degree hours build up during this transport. The  bottom line is that due to the cooling process during the stay at the Holex facility, the complete journey will have very little effect on the vase life of the products.

Vacuum cooled boxes (blue) versus non-vacuum cooled boxes (red): by looking through an infrared camera, temperature differences become very clear.

Holex Flower is the first Dutch flower export company that is accredited for the FlowerWatch Distributor Standard, as a part of the FlowerWatch Quality Standard for Global Flower Supply Chains. This standard makes sure that Holex uses a set of critical control points, in order to prevent unwanted “temperature exposure” and organises a fast and efficient supply chain. This results in a minimum loss of vase and shelf life, as well as loss of quality and value.

Jeroen van der Hulst, CEO of FlowerWatch says, “Holex Flower has proven to take working with a complete cold chain, from grower to wholesale florist, very seriously. Besides the adjustments and expansions of their production process, also the employees have been extensively educated the past year. They have passed all FlowerWatch tests with great success.”

Holex’ wholesale customers around the globe can also contribute to a prolonged shelf life of products. First, they should understand that the earlier they give in their order on their supplier’s webshop, the more time the latter has to cool the shipment for transport.

The irony is that international customers may be inclined to think to get “fresher flowers” when  ordering them later on in the week. However, when the degree hour rule is kept in mind,  flowers will arrive fresher at their destination because they are cooled down better.

It is important that upon arrival at the wholesale florist, flowerss must be immediately  stored in a cold room with a set point of temperature between 1-2°C (33.8-35.6°F). Avoid peaks higher than 4°C (39.2°F)! Take care of continuous monitoring and meticulous registration of the temperature.

Any temperature changes in cold rooms should be noted . It is also very important that all flowers in the cold room are cooled evenly so they should be positioned properly ensuring that there is even air circulation throughout the cold room.

Furthermore, all areas where flowers are stored or processed must be kept free of any external ethylene sources, and free of flowers older than 7 days to prevent to development of sources of botrytis.