It depends on which cider you mean. Hard cider is always fermented, producing alcohol typically between 0.5 and 8.5 percent ABV. The fresh apple cider sold in jugs at grocery stores and farm stands is not intentionally fermented, though it can start fermenting on its own if left unrefrigerated. The confusion exists largely because the word “cider” means different things depending on where you are and what’s on the label.
Why the Word “Cider” Causes Confusion
In the United States, “cider” or “apple cider” usually refers to unfiltered, unpasteurized apple juice. It’s the cloudy brown stuff sold in the fall, pressed straight from apples with no fermentation involved. “Hard cider” is the alcoholic version. In the UK, Australia, and most of Europe, “cider” means the alcoholic drink by default. If you’re in London and order a cider, you’re getting something fermented. If you’re at a New England orchard and someone hands you a cup of cider, it’s just juice.
U.S. labeling rules reflect this split. The Alcohol and Tobacco Tax and Trade Bureau (TTB) regulates cider as a type of wine when it contains at least 7 percent alcohol by volume. Products below 7 percent ABV aren’t even required to carry a federal alcohol label approval. So a 5 percent hard cider at your local bar is regulated differently than a 9 percent one, even though both are fermented.
How Hard Cider Fermentation Works
Hard cider starts as apple juice. Yeast consumes the natural sugars in the juice and converts them into alcohol and carbon dioxide. That’s fermentation in its simplest form, the same basic process behind wine and beer. The juice can come from freshly pressed apples or apple concentrate mixed with water.
Cidermakers choose between two approaches to yeast. Commercial strains produce consistent, predictable results every time and can tolerate higher alcohol levels. Wild yeast, naturally present on apple skins and in orchard environments, creates more complex and variable flavors but behaves less predictably from batch to batch. Many craft cidermakers use wild fermentation deliberately for its character, while larger producers rely on commercial yeast for uniformity.
Primary and Secondary Fermentation
Fermentation happens in two stages. Primary fermentation is the vigorous phase where most of the sugar gets converted to alcohol. You’d see visible signs if you watched: bubbling, foaming, and activity in the airlock on the fermentation vessel. This stage typically takes one to three weeks and works best at temperatures between 60 and 75°F.
Once the initial burst slows down, the cider moves into secondary fermentation. This is a quieter phase focused on flavor development and clarification. The cider sits for anywhere from two weeks to several months, depending on the style the maker is after. A simple, light cider might spend just a couple of weeks in secondary. A richer, more complex cider could age for half a year or longer. Temperature, yeast strain, and sugar content all influence how fast and how far fermentation progresses.
Where Carbonation Comes From
Not all hard cider is bubbly, but most commercial versions are. The fizz comes from one of two methods. Bottle conditioning involves adding a small amount of sugar, called priming sugar, to the cider just before bottling. The yeast still alive in the cider ferments that sugar inside the sealed bottle, producing carbon dioxide that dissolves into the liquid. This is the same technique used in traditional champagne and many craft beers.
The faster alternative is force carbonation, where CO2 is pumped directly into the cider under pressure. This is how most large-scale producers do it. The result tastes similar, though bottle-conditioned ciders sometimes have a slightly different texture and may leave a thin layer of yeast sediment at the bottom of the bottle.
Can Fresh Apple Cider Ferment on Its Own?
Yes, and this is where things get interesting for anyone who’s bought a jug of fresh cider and forgotten about it. Unpasteurized apple cider contains wild yeast naturally. Left at room temperature, those yeasts will start consuming the sugars in the juice and producing small amounts of alcohol and CO2. You might notice the jug starting to expand, or the cider developing a slightly fizzy, tangy quality. That’s spontaneous fermentation happening.
This is why fresh cider has a short shelf life and why most commercial brands are pasteurized or treated with preservatives. Pasteurization kills the yeast and bacteria that would otherwise kick off fermentation. If your cider is pasteurized and sealed, it won’t ferment. If it’s raw and fresh from a press, it absolutely can, and will, given enough time and warmth.
Alcohol Levels in Hard Cider
Most hard ciders fall between 4 and 7 percent ABV, putting them in roughly the same range as beer. The U.S. tax code defines hard cider specifically as containing at least 0.5 percent but less than 8.5 percent alcohol by volume. Anything at 8.5 percent or above gets taxed at a higher rate as standard wine rather than cider, which is why you rarely see commercial ciders above that threshold.
The alcohol content depends on how much sugar was in the original juice and how completely the yeast fermented it. Sweeter apple varieties produce juice with more sugar, which can yield higher alcohol if fermented fully. Many cidermakers stop fermentation early or back-sweeten the finished product to keep some residual sweetness, which also keeps the ABV moderate.