Bourbon whiskey produced by one distiller at one distillery during a single distilling season, aged for at least four years in wooden containers in contact with the wood, and bottled at exactly 100 proof. Except for permitted physical treatments such as filtration or chill proofing, it may not be altered from its original character; only pure water may be added to reduce it to bottling proof. Domestically produced bottled-in-bond bourbon must also identify the distillery where it was distilled and warehoused and the distilled spirits plant where it was bottled.