For those unfamiliar with this fruit (as I was a few months back) this is a cross between a mandarin orange and a kumquat. It has all the extreme tartness of the kumquat while also exhibiting a great orange flavor and aroma. I first ran across this fruit while talking with the brewers at Infusion Brewing Company in Omaha, Nebraska. They pulled a few of these out of the cooler, cut and squeezed them into a glass and passed it around for a taste.
They had obtained a flat of these and were trying to figure out how to use them in a beer. My first thought was to use them in a saison while others thought a wheat beer would be the best base. I managed to talk them out of a couple pounds for my own experimentation. A few days later, Zymurgy came out with a feature article on brewing with kumquats. The article was somewhat helpful on how much to use and how to use them but I was still trying to work out my base beer for this. I had a belgian dark strong in secondary that I had been planning to dose with a concentrated sour cherry juice concentrate so I decided to substitute the mandarinquats for the sour cherry.
I suspended a hop bag (actually a sanitized paint strainer bag) in a keg and cut and squeezed two pounds of the quats into the bag then tossed the rinds and seeds into the bag too. I sealed and carbonated the keg and let it sit for a week. I bottled up a few bottles from the keg for a local competition and got decent scores (33 and 34) but I was a bit disappointed with the beer as I was hoping for a little more sour.
I then let the keg sit for another month and didn't taste it again until I served it at a beer festival last weekend. That additional month of sitting with the rinds, seeds, and pulp had changed it into a totally different beer. It had turned into a fantastic beer with exactly the character I was looking for. Great orange/citrus aroma, tart sourness, and subtle but noticeable citrus flavor backed by the nice malt backbone of the Belgian strong.
The Infusion Brewing Company attempt used an American wheat beer as a base but this did not have the backbone to support the flavor of the mandarinquats. There was no real balance at all.
I will be doing this beer again when the quats become available again. Next time I will change the hops a little to use some Sorachi Ace and Amarillo. I will also consider the addition of a little coriander to the boil.
If you get a chance to brew with these wonderful fruits give it a shot. I think you will love it.