While I can share the ingredients for soba noodle making, and the photos demonstrate technique, it takes the daily practice of ten years to achieve the results for the soba noodles I ate in the mountains of Japan made by Master Soba Noodle maker Hajime Matsuoka.
He explained that he uses a ratio of 9:1 buckwheat to wheat flour and adds approximately 43-45% water by weight (depending on the humidity.)
Master Hajime Matsuoka was also insistent that the soba noodles must be consumed within half a day or they loose texture and aroma. Our demonstration was at dusk (and our soba noodles were served as the last course in our dinner that night.) Not surprisingly, they are the best soba noodles I’ve ever eaten.