operation, but in 10, 15 or 20 years, we will have a real problem. reporter: part of the problem is that many dutch people view the windmills as props.lour comes from the supermarket. >> we didn't know you could get flour there. i had no idea. >> this is more convenient. but maybe it tastes better from the mill? reporter: for leen lagerwerf, there's no question. whether it's rye, wheat, or spelt flour, his mill in the town of oisterwijk supplies the bakeries in the area. >> when the old millstones sing as the saying goes, and when the flour feels soft and slightly sandy, then we know the quality is good. reporter: of course, tourists can also stop by to watch and listen to the traditional craft. these people have come specially from spain. >> we have come here because it's really popular that holland is full of windmills. reporter: the windmills themselves are likely to last. but whether they will keep providing bakers with flour, and whether young dutch people like koen heikop will be memorizing the blueprints of mills in the future, that is increasingly unclear. michelle: it's great to see a young person determined to carry on trad