It was in the 18th century that the solera system wasdeveloped ; a system whereby interconnecting wooden casks arestacked in tiers , the young sherries being poured into the casks atthe top and the mature sherries being drawn out of the casks atthe bottom 在18世纪人们研制成功了索尔拉制酒法,即在木桶内加隔层上下相通,刚酿成的雪利酒装在桶的顶部,酿熟的雪利酒从木桶的底部抽出来。