Tell anyone who hasn’t heard of the style that you’re drinking an oyster stout and you’re sure to get strange looks. These looks are usually followed with questions like “Is it slimy?” and “Why are you drinking that?” What these folks don’t know, however, is that the use of oysters, and more specifically their shells, in beer is quite normal and is actually a very clever feat of brewing science. It’ll always sound weird to some people, but with a bit of background knowledge on the technique and its history you should be able to answer those nagging questions and maybe even convert a naysayer or two.
The history of seemingly inappropriate ingredients like oysters finding their way into beer recipes is longer and more widespread than you may think. Throughout the brewing world the ever potent blend of ingenuity and necessity has led to the addition of many adjunct ingredients to the fundamental beer recipe of barley, hops, water, and yeast. For hundreds of years in Belgium, spices and herbs have been used to flavor witbier, fruit to contrast and complement the sour punch of lambic, and whatever happens to be lying around the brewery to make saisons. Across the pond, the big American brewers have been adding rice and corn to their beer for over a century. More recently, the envelope-pushing American craft brewers have experimented with adding just about every possible ingredient to their beer recipes. Everything from habenero peppers, to marshmallow fluff, to bacon have found their way into the brewhouse. But few ingredients are as resourceful and effective in improving a beer as the oyster and its shell. In fact, it’s a technique that was developed over a hundred years ago in Victorian England and has been used in one form or another ever since. Of course as any old tale goes, there are several ways to tell the story, but here’s a general outline.
Oysters were the ultimate bar snack among pubs of the day. Cheap, salty, and plentiful, they were perfect to wash down with the standard working man’s bitter and roasty dry stout. The association between oysters and stouts became so strong that stouts began to take the name “oyster stouts,” even though oysters were not used in their production. Eventually somewhere, someone in England put two and two together and actually tried adding oyster shells to the boiling wort of their stout. Either by a stroke of genius or pure luck, the end result was a balanced, clear, full-bodied beer with little residual oyster taste.
Few ingredients are as resourceful and effective in improving a beer as the oyster and its shell.
Now let me use a bit of chemistry to explain why this makes perfect sense. The roasted malts used to make a dry stout contribute a fair amount of acidity to a beer. In classic stout brewing cities like London and Dublin, the water has a high calcium content, which balances out the acidity brought on by the malts. If the water used by the brewery lacks this calcium, however, the stout could end up a sour, acidic mess. Oyster shells, on the other hand, are composed mostly of calcium carbonate, the same acid-buffering molecule in the antacid tablets that soothe your sour stomach. Thus, adding shells to the brewing process when boiling the extracted grain sugars will result in a cleverly balanced and buffered stout.
But, that’s not the only benefit of oyster shells. They act as what brewers call a “fining” agent. When calcium carbonate is in a hot, liquid environment, positively charged calcium ions are released. These ions attract the negatively charged brewing sediment in the beer, forming a new complex that quickly falls to the bottom of the brewing vessel, effectively clarifying the beer’s appearance. Of course, the question on everyone’s mind is how these oysters affect the flavor of the beer. Luckily, oyster shell flavors are so delicate that they simply boil out and become nearly unrecognizable. It isn’t clear whether or not the addition of shells was intended to be a gimmick or if it was actually a brilliant example of applied chemistry, but either way the trend caught on and oyster shells became a commonplace ingredient in stout recipes. Then someone took things a step further.
According to craft beer legend Michael Jackson, the first incident of actual oyster meat being used in beer occurred in New Zealand in 1929. Just like adding oyster shells, the addition of oyster meat makes a lot of sense if you think about it. Oatmeal is a common adjunct to stout recipes, as the proteins bulk up the body of the beer while the fat content smooths out the mouthfeel. The flavor contribution of oatmeal is small, but there’s a discernible sweet and nutty flavor in most oatmeal stouts. Just like oatmeal, oyster meat is loaded with protein and fat, giving the brewer a full-bodied, smooth beer with an air of the sea rather than a bowl of oatmeal.
But not everything about brewing with oysters is perfect. Properly storing and cleaning oysters for use in beer is a very labor-intensive process that must be added to the already intense process of brewing. Additionally, oysters are a natural product, meaning there’s a great deal of variation from bushel to bushel. Because of this, and the added cost of stocking the mollusk, brewing with oysters fell out of favor for awhile, substituted instead with various body-enhancing extracts and calcium carbonate powders.
While these substitute products are still widely used, the oyster stout tradition has seen a mild resurgence in recent years. Up-and-coming English craft brewers are reviving their ages old tradition and their American counterparts are experimenting with shellfish in a wide array of applications. This isn’t just limited to oysters and stouts, either. Pennsylvania’s leading experimentalists Tired Hands Brewing Company recently brewed a stout that incorporated escargot shells into the process. North Jersey newcomers Carton Brewing are taking it even further, using lemongrass and local clams instead of the traditional coriander and salt to brew their take on the classic German Gose.
Hopefully this renewed interest in brewing with oysters sticks around because it’s a genuinely brilliant example of utilizing available resources and a bit of science to solve a problem. Of course, some people will always be turned off by the idea of shellfish in their beer but, after trying one, it becomes evident that the benefit to the balance and body far outweigh the fishiness. The best way I’ve heard the flavor of the oyster contribution described is as “a phantom brine.” In your mind you want that flavor to appear on your palate, but you can’t quite say for sure that it’s actually there. So, if you have a disbeliever on your hands, just let them have a taste and tell them afterwards that it has oysters in it. Chances are they’ll love it and make no mention of oysters at all. Just make sure they aren’t allergic to shellfish first.
Here are four takes on the oyster stout style that I’d recommend. Each beer incorporates oysters into the process in a slightly different way with different results. It’s always an interesting exercise to taste these beers and attempt to discern that elusive shellfish brininess.
San Francisco, CA. 7.9% ABV. $10 for a four-pack
The richness of this stout parallels the characteristic sweetness of the Hog Island Oyster Company’s Sweetwater oysters, whose shells are used to make the beer. It’s definitely bigger and chewier than your average oyster stout, with milk chocolate, light roast coffee, and leather notes packaged in a dense body that’s accented by a bit of salty seaweed. The finish is chalky with loads of sweet toffee flavors.
Frederick, MD. 5.5% ABV. $8 for a six-pack
This American take on a very traditional English oyster stout utilizes one of Virginia’s finest, the Rappahannock oyster. It’s got a bitter coffee and chocolate flavor, low alcohol, and immense drinkability of the classic English style, but thanks to the intense brine of these Mid-Atlantic mollusks, there’s a more apparent saltwater note on the finish.
Dublin, Ireland. 5.2% ABV. $5 for a 12oz bottle
Straight from the land that made the stout famous, this quintessential example uses whole oysters shucked straight into the conditioning tanks. This one drinks much like the classic dry stouts of Irish heritage, with plenty of toasted bread, bitter chocolate, and hints of vanilla. The oysters show up as a chalky, smoke enveloped sweetness that sticks with you after each sip.
Meer, Belgium. 8.5% ABV. $14 for a 750mL bottle
Oyster stouts are by no means a Belgian tradition, and this take on the style is certainly not traditional in any way. This beer starts out like a regular stout but before fermentation it’s filtered through oysters from over the border in the Netherlands. It’s then fermented with a Belgian yeast strain, giving it flavors very similar to a Trappist Quadrupel, with raisin, toffee, banana, and smoke. Take a sip and wait a few minutes and you may just feel a tingly salty sensation, like you just ate a handful of salt-covered pretzels, grace the top of your tongue.