Finely grind the flaxseeds with the sunflower seeds in a blender. Peel the carrots and celery, and grate them finely. Grind the spices, and mix all ingredients well. Spread the mixture about 2mm on backing paper, and draw predetermined breaking points into the dough with a bench scraper. Let it dry at low temperature in the dehydrator. We dried the hearty crackers at 50°C for about 18 hours. If you want to prepare the crackers raw, you need to dry them at less than 40°C and a bit longer.