My sister had two black schnauzers. She took them to the groomers on a regular basis, and even then they had reddish beards. Dont really know what you can do about it with the breed, other than keep it shaved. I have heard that some owners rub small amounts of vaseline into their beards and then blow dry them on low heat to distribute it through the hairs. Its supposed to form a protective coating , but not having done it myself, i couldnt guarentee anything.
If you are a dog and your owner suggests that you wear a sweater, suggest that he wear a tail.