Combine vinegar and peppercorns. reduce in a small saucepan until almost all of the liquid has evaporated. Add the water to the reduction. blend and strain.
Add the water and reduction to the egg yolks in a large metal bowl over simmering water. Do not allow the bowl to touch the water. Whip the egg yolks with a wire whisk, over the simmering water, until the yolks form ribbons. Gradually add the clarified butter, whipping constantly. Add the lemon juice and cayenne, and adjust the seasonings to taste with salt and pepper. If necessary, place the bowl in a pan of warm (not hot) water until served. When ready to use the sauce, beat evenly with wire whisk for 30 seconds until smooth.
Keep the sauce warm in a bain marie (warm water bath) or a Thermos. Do hot hold for more than 90 minutes; if you need to hold the sauce longer, discard the old one after 90 minutes and make more.