Products listed as Certified are preferable to those listed as Acceptable. Many Irish Whiskies are aged in casks that previously held sherry, sauterne, port or other wines. Others have special "finishes" or multiple "maturations" that include aging in wine casks. All of these practices raise kashrus concerns. The cRc policy is that Irish Whiskey is permitted unless the label or company website state that it is aged in a wine cask, has a special finish, or an extra maturation (as noted above). The label and company website of each bottle should be carefully checked before using it, and one should avoid wording such as double or triple finish, double or triple matured, dual casks or finish, European or French casks, Madeira finish, port, sauterne, or sherry and other wine casks. The cRc listings of acceptable Irish Whiskies includes products that are certified and/or known to not have been aged in wine casks.
