In a large bowl, stir yeast into water to soften. Add beer, mustard, horseradish, oil, sugar, rye flour, salt, caraway seeds, and 2 cups unbleached flour. Beat vigorously for two minutes.
NOTE #1: I'm not a fan of caraway seeds. This may sound odd, but I love the flavor just not the actual seeds. To get the flavor without the seeds, I grind the 2 tablespoons of seeds into powder.
NOTE #2: a 12 ounce bottle of beer yields about a cup and a half. If you only have one bottle, use water for the remaining ½ cup.
YET ANOTHER NOTE: I never use a well-greased baking sheet. I always use parchment paper. In this case, I let the dough rise on the paper and then used it to transfer the risen dough to the baking stone.
About 15 minutes before baking, preheat oven to 375 degrees. I used a baking stone for this recipe.
Immediately remove bread from baking sheet and cool on a rack