The first Friday of the month means one particular thing for beer bloggers: The Session! It’s a monthly collaborative blogging effort where we all write a post following a common theme, which is chosen each month by a different blogger who gets the “hosting” duties. This month’s host is Ashley Routson, better known amongst the bloggerati as The Beer Wench, and true to Ashley form (that’s a good thing!), she has picked a perfectly appropriate topic for October: Frankenstein Beers.

Many craft brewers are like Frankenstein. They have become mad scientists obsessed with defying the laws of brewing and creating beers that transcend style guidelines. These “Frankenstein Beers” challenge the way people perceive beer. They are freaks of nature — big, bold and intense. The ingredients resemble those of a beer and the brewing process might appear to be normal, but some aspects of the entire experience are experimental, unorthodox and insane.

An altercation with these beers produces confusion in the eye of the taster … is it a beer, or a monster?

Your mission, should you choose to accept it, is to write a blog post on “Frankenstein Beers.” There are no rules about how to write about this topic — feel free to highlight a Frankenstein brewer, brewery, beer tasting notes … or just your opinions on the concept.

This (intentionally) ties in with this month’s Theme Week I’ve been doing here at The Brew Site: Unusual Beers. So in addition to drinking and reviewing a number of unusual beers (I notice they were all—unintentionally—herbal/botanical in some way), I’ve been thinking about this topic of “Frankenstein” beers.

From one end of the spectrum, it’s perfectly valid to call any non-Reinheitsgebot-adhering beer a “Frankenstein” beer: once you start breaking the boundaries of the malt-hops-water-yeast cycle and throwing in other ingredients, you’ve got the “monster” beer in the eyes of the purists. Of course, without this (constant) experimentation we wouldn’t have the vast array of beer styles that exist today—so it’s also perfectly valid to call any such styles Frankenstein beers.

The next step up that scale is to consider the established styles—be they Reinheitsgebot-friendly or not—as “normal” and thus the various beers we might consider “extreme” or some other such adjective the Frankensteins: the Imperial IPAs, the Cascadian Dark Ales, the various Belgian styles blending beers, the fresh hop beers… In fact this week I’ve been thinking a lot about how the autumn season’s “unusual” beers—the fresh hop beers and the pumpkin beers—qualify as Frankensteins, and almost wrote about one (or both) of them.

(But, I’ll be doing Pumpkin Beer Week later this month as it is, and in a way pumpkin is almost a normal style of beer—after all, it’s been present in the Americas in one form or another since the Colonial days.)

Ultimately I decided that, of all styles of beer that can (and do) qualify as the Frankensteins, I had to drink and write about a beer that signifies what I think defines the original Frankenstein style: the sour wild ale.

These are the true “monstrous” beers—brews that are purposefully infected, inoculated with wild, unpredictable yeasts and bacteria, left to sour and bubble away for years at a stretch, often quite ugly along the way. Really, who was the first person who looked at the moldy, snotty mess that these beers can look like while they’re fermenting and think, “Yeah, I’m gonna drink that“? Truly a class of beers worthy of this month’s topic.

So to celebrate The Session and do an actual beer review (feels like the last few Sessions have been more abstract than liquid), I stopped in at my local Whole Foods today and selected an appropriately sour beer to drink and review: Monk’s Cafe Flemish Sour Ale. This beer is brewed by Brouwerij Van Steenberge in Belgium for the famous Monk’s Cafe in Philadelphia. It’s a 5.5% ABV Oud Bruin style of sour ale—a sour brown.

Appearance: Deep and clear brown that’s bloody red when held to the light. Light tan head piles up on top with the pour.

Smell: Sour notes punctuated with sweet rock candy and funky Brett notes. The tart is a bit “cherry.”

Taste: Mellow, ascetic tartness (vinegar) with very crisp and nicely fruity wine-like presence. Really nice, smooth. Sour cherry mousse and the vinegary tartness punctuates the fruit.

Mouthfeel: Super smooth, crisp and fruity with a light(ish) body that finishes dry (sour).

Overall: Really good—the sour blends with other flavors amazingly well (and the funk is minimal). Graceful and elegant.

On BeerAdvocate, it scores an overall grade of B+. On RateBeer, it scores 3.47 out of 5 and is in their 92nd percentile.