In today's synagogues there are more and more choices of whiskies available at kiddushim. For many the mark of a good kiddush is the amount of varieties of single malt whiskey available. Many take for granted the kashrut status of these whiskies thinking all whiskies are kosher.
Are all whiskies kosher? Well like most things it depends. Some are fully under rabbinic supervision, some are recommended and some are not recommended. The cRc - Chicago Rabbinical Council does not recommend all whiskies, including many whiskies that a lot of us have in our liquor cabinets. The cRc writes "many scotches are aged in casks that previously held sherry, sauterne, port or other wines. Others have special 'finishes' or multiple 'maturations' that include wine. All of these raise kashrut concerns. The cRc policy is that scotch is permitted unless the label states that it is aged in a wine cask, has a special finish or an extra maturation." To see the cRc stance in more detail please click here.
The OU - the Orthodox Union, has a very different policy based on the halakhic ruling of Rav Moshe Feinstein.

Rav Moshe takes the lenient position there too and rules
that it applies to all
liquids. However, in his responsa concerning both disputes, he adds that even
though he rules leniently on these issues, it is worthwhile to be stringent.
Rav Moshe felt that since in alcoholic beverages the ratio of non-kosher wine
or other products to liquid is usually more than one to sixty,
it is worthwhile to refrain from drinking alcoholic beverages that contain
wine, glycerin or other non-kosher ingredients (YD, siman 62). He writes that
he only drank such beverages if someone was making a lechaim and would have
been insulted if he did not partake." To see the OU position in more detail click here.
I found a great website which lists kosher certified whiskies, whiskies which are permitted to drink but not certified and non-kosher whiskies. Click here for the link. It was interesting to see that some whiskies have kosher certification from the kashrut agencies but they are not listed on the bottles.

It goes without saying but I will state it anyway, drinking should be done responsibly and only over the legal age to drink. I do not endorse underage drinking or the promotion of alcohol to minors or a binge drinking culture.
As we are coming up to Pesah it is important to note that whiskey as well as beer and vodka are hametz and need to be part of your items that are sold before Pesah or consumed in the next few weeks.
P.S. A good friend sent me a link on a related issue. It is based on the idea that somethings may only be kosher if they don't have a hechsher . The reason being that the hechsher is done for the Jewish market and therefore everything in it must be 100% kosher even if it is less than 1/60th as we have a principle that we don't nullify something lechatchila - as best practice. Only after the fact can we nullify something. Anyway please read the link on modern Torah leadership.
As we are coming up to Pesah it is important to note that whiskey as well as beer and vodka are hametz and need to be part of your items that are sold before Pesah or consumed in the next few weeks.
P.S. A good friend sent me a link on a related issue. It is based on the idea that somethings may only be kosher if they don't have a hechsher . The reason being that the hechsher is done for the Jewish market and therefore everything in it must be 100% kosher even if it is less than 1/60th as we have a principle that we don't nullify something lechatchila - as best practice. Only after the fact can we nullify something. Anyway please read the link on modern Torah leadership.