Last updated:
Whether Guinness is a lager is one of the most common beer questions I encounter from people who are just starting to pay attention to beer styles, and the answer illuminates a genuinely important distinction in brewing that most casual beer drinkers don’t think about. The short answer is no, Guinness is not a lager. The longer answer explains what Guinness actually is and why the confusion arises, which is more interesting and more useful for building beer knowledge.
What Guinness actually is
Guinness Draught is a dry Irish stout, a specific style of ale brewed with roasted barley (which gives the coffee and chocolate flavors and dark color), nitrogen dispensing (which gives the creamy cascade and dense head), and top-fermenting ale yeast (Saccharomyces cerevisiae) at ale fermentation temperatures. The defining characteristics of the style: extremely dry finish from highly attenuated fermentation, pronounced roasted barley bitterness (distinct from hop bitterness), dark opaque color, and the nitrogen-driven cascade that forms the characteristic creamy head. Guinness Draught is 4.2% ABV, a relatively low alcohol content for a stout, achieved through a recipe that maximizes dryness and attenuation rather than residual malt sweetness.
Lager vs ale: the fundamental difference
The lager versus ale distinction is entirely about yeast and fermentation temperature, not color, strength, or flavor profile. Lager yeasts (primarily Saccharomyces pastorianus, a natural hybrid) ferment at cold temperatures (5–10°C) and settle to the bottom of the fermenter, “bottom-fermenting” yeasts. They produce clean, crisp fermentation character with minimal ester production. Ale yeasts (Saccharomyces cerevisiae) ferment at warmer temperatures (15–22°C) and rise to the top, “top-fermenting” yeasts. They produce fruity esters and other fermentation-derived flavors. A dark beer can be a lager (Munich dunkel, schwarzbier, dark American lager) and a pale beer can be an ale (American pale ale, blonde ale, Kölsch). Color does not determine lager versus ale classification. Guinness uses ale yeast at ale fermentation temperatures, it is an ale in every technical sense, specifically a dry Irish stout.
Common Questions
Why do people think Guinness is a lager?
The Guinness-as-lager confusion comes from several overlapping sources. First, in everyday language “lager” is used colloquially in the UK and Ireland to mean any commercially produced, mass-market beer, as in “I’ll have a lager” meaning any cold beer at a pub, not specifically a bottom-fermented cold-conditioned beer. In this colloquial sense, Guinness is sometimes contrasted with “lager” rather than being placed in the same category, which can confuse people who hear this exchange and assume “lager” is a flavor or color category. Second, Guinness’s smooth, nitrogen-carbonated character differs from the CO2 carbonation of most ales, making it feel like a distinct product category to drinkers who know ale as bubbly and bitter in the IPA sense. Third, casual drinkers often categorize beer by color, pale beer = lager, dark beer = stout = some special non-lager thing, without understanding that color and fermentation method are independent variables. The correct understanding: Guinness is a stout, which is a subcategory of ales, which is one of the two main beer fermentation categories alongside lagers. Dark does not mean lager or not-lager; fermentation yeast and temperature determine that classification.
