WILD FERMENTATION VS. CULTURED FERMENTATION
If you have been paying attention to the craft beverage market lately, you may recall seeing the words “wild fermented” on the label. Beer and hard cider makers have especially embraced the wild fermentation movement. You may be wondering though, what is wild fermentation, how does that affect the drink, and why has it become so popular over the last few years?
When a beverage like beer, wine, mead, or cider is created it starts its life as a sweet
liquid full of natural sugars. In beer the sugars come from grains, in wine the sugars are found in the grapes, in mead the sugar comes from honey, and with cider the apples’ juice is naturally very sweet. In order to get the alcohol content from any of these liquids there must be a fermentation process. The fermentation process is what occurs when microorganisms called yeast begin to eat the sugar in these liquids. When the hungry little yeast cells eat the sugar, they give off by-products which primarily consist of a) alcohol and b) carbon dioxide. So effectively, the more sugar you begin with in your liquid (which is called must), the higher the alcohol content will be in the final product.
There are yeast cells present in every orchard and they live on every apple tree and cover the skin of every single apple on every apple tree. These yeast cells are what cider makers call “wild yeast”. In order to make a wild fermentation, all a cider maker must do is provide the wild yeast with suitable conditions in the juice for the yeast to pro-create and eat the naturally available sugars. With a wild fermentation the cidermaker really doesn’t have a whole lot of control over which yeast strains take control and gain dominance in the fermentation process. There may be many different yeast strains naturally occurring in the orchard and they will all be competing in the apple juice for the resource of sugar. Some strains will be more aggressive and beat out others in the fight for these sugars. These more aggressive strains will typically affect the fermentation characteristics more than the others.
Wild yeast strains will differ from region to region. One orchard may have much different wild yeast characteristics than another orchard that is only a few miles down the street. These variations in wild yeast will give the cider different characteristics and cider makers who choose to take advantage of wild fermentation are giving up some of their control over the fermentation process in order to allow the cider to naturally express itself as a product of its location.
On the other hand, a cider maker may choose to use a commercial yeast strain in order to have more control over the fermentation process and have his or her final product be more of an expression of their particular vision for their cider blend. In order to achieve this, they must cleanse the must of any wild yeast and start with a blank slate. This is achieved by adding sulphites to the must in order to kill the wild yeast strains before adding the particular yeast strain that has been cultivated to match the cider maker’s desired characteristics.
In my opinion there is no right or wrong way to approach cider making. There are, however, differing philosophies when fermenting cider and whether or not you use cultured yeast does play a crucial role in these philosophies. On one hand, if you want the cider you make to be a full expression of a particular orchard or region and the terroir of the region, then let the cider go wild. The cider maker’s role in this style of cider making is more of a caretaker of the apples to make sure they make it from the tree to your bottle. The apples and microbes are in full control to do as they will. On the other hand, if the cider maker envisions him or herself as a chef crafting a recipe so that the final cider is a result of their craft, then they will most likely be working with a predictable commercial yeast strain.
I personally enjoy working both ways. With the Colonial Cider experiment, we let the cider ferment naturally. This only seemed right considering the spirit of the experiment. The cider will turn out how it will and the flavor will completely capture the experience. We did not have a vision in mind for how the cider would taste. We were focusing on the process and the cider will turn out to be its own expression of the terroir of western Massachusetts. However, I sometimes really enjoy having control over my apple varieties, yeast, and fermenting conditions while creating a blend that purposefully represents my vision. Then I can tweak that blend later so that the finished result is something that I am proud of.