Store at room temperature, away from heat and moisture. "Shiitake and "Umami is the Japanese word. However, today, most of the shiitake is made in China or cultivated using an artificial substrate such as sawdust. Our Japanese Dried Shiitake are naturally cultivated outdoors using whole logs. You might not have yet tried natural made Shiitake. Nature made Shiitake contains large amounts of Guanylate which gives glutamate a much more intense Umami taste. Tips for Rehydration For the most delicious Shiitake, please soak in cold water for 24 hours in the fridge. To reduce soaking time, take out the Shiitake one hour after you started soaking the mushrooms, chop into small pieces and soak for another hour and then use as needed. Directions 1) Lightly wash with water and scour dust from the Shiitake. 2) Place the Shiitake in a container with enough water to completely cover the mushrooms after they sink. 3) Put into a less than 10C/50F fridge for 5-24 hours to improve the Umami. 4) To check for readiness, touch the stem. The joint stem is the hardest part of the Shiitake. When the stem feels some when squeezed, the Shiitake is ready to be used. 5) Cook for ten minutes or more, it increases Umami, becomes even tastier. Our Shiitake are exposed by ultraviolet light in the factory so that we can further enhance and guarantee the amount of Vitamin D. USDA has reported that the most Vitamin D rich ingredient is brown mushrooms, exposed to ultraviolet light, it has 1,110 IU/87g. Our dried Shiitake will become 4xs heavier after rehydration. If we compare our Shiitake with USDA data, the following calculation can be made. 9680 IU (242g) / 100g (dried shiitake) 4 2,420 IU (61g) / 100g rehydrated shiitake 1,936 IU (48g) / 80g (Our Shiitake) In conclusion, our Shiitake has the most Vitamin D content of any natural foods.