Thanks for your reply. The whole production process would have to be overseen by an individual certified in the laws of kosher after which it would be "stamped" with a seal of approval (the logo would be added to the product label). Thanks for your suggestion, but it doesn't look as though it is certified.
Thank you so much, Simon. And I shouldn't increase any other alcohol? I knew it wouldn't be exactly the same, but until an elderflower liqueur gets certified, this is what I have.