We arrived to Cologne early afternoon and we were able to book last minute. My husband was very happy with the tour, tasting and information presents. We were a group of 9 people (5 actual tour participants and 4 others connected with the tour guide.). It was a great experience having so many locals along and sharing their insight.
I would definitely recommend this tour. Our tour guide was knowledgeable, easy to understand and entertaining.
Things to note: we booked through Freetour.com. They took a deposit with the reservation but then expected us to pay cash for the remainder due. This info was not provided in advance. Tipping the tour guide for this paid tour was expected just like the free tours. You get three, 3EUR beers on the tour and then pay out of pocket for any additional purchases.