David from Florida asks:
What is the best yeast and temperature combination to get the Belgian spice flavor without adding spices? I have tried several combinations but have not found the right one yet. Could it also be more dependent on grain, hop and water choices? Do you have any recommendations to get there?
Also, I have heard rumors of Orval being offered on tap, but only behind the monastery doors. Have you had the opportunity to try this and what did you think of it?
Stan answers:
Every one of the factors you mention can contribute, but if you can brew enough batches and change just one factor (be it an ingredient or one part of the process) at a time you should be able to find the balance you want. That spice flavor you are looking results from a phenol known as 4-vinyl guaiacol, the same phenol that gives German hefeweizens their unique clove-like aromas and flavors.
Most yeasts sourced from Belgian monasteries, Rochefort is the exception, produce pretty high levels of 4-vg. You can promote this even more with a 10-minute rest at 113-115° F, which is what German brewers do while making hefeweizens, although this really shouldn’t be necessary. Beyond the production of 4-vg, of course, is the matter of perception. If you restrain fermentation temperature throughout you’ll limit ester production, which will promote the perception of spice (clove).
The challenge is finding the balance, because you want plenty of fruity esters. Additionally, production of esters, higher alcohols (more of the aromas/flavors you expect in these beers) and proper attenuation all go hand in hand. That’s why pitching in the range of 62° F to 64° F and letting the temperature rise naturally (heat created during fermentation) seems to work so well.
Yes, Orval is served (don’t know if it is all the time) on tap at the monastery. The excitement of drinking it there (“Hey, look at me, I’m drinking draft Orval”) makes taking any proper sensory notes impossible. If you cannot enjoy the “halo effect” in a monastery where might you enjoy it?