Oat Milk Brands Compared: Oatly vs Califia vs Minor Figures and Who Actually Wins

Oat milk is now a $4.4 billion global category (2023 market value, according to Grand View Research), having grown from a niche Scandinavian product to the world's best-selling plant-based milk alternative in under a decade. In the UK, oat milk overtook soy milk as the most popular plant-based milk in 2020 and now accounts for approximately 40 percent of all plant milk sales by volume. In the United States, it went from approximately $4.4 million in annual retail sales in 2017 to over $290 million by 2020, a growth rate that outpaced every other food category of comparable size. The category is now crowded with dozens of brands, and the differences between them are significant enough to affect your morning coffee, your baking results, your blood sugar, and your grocery budget. This comparison covers the leading brands by use case, with specific attention to barista formulations, nutrition, and the glycaemic index issue that affects a substantial portion of the population.

How Oat Milk Is Made: The Science Behind the Taste and the Glycaemic Index

Oat milk production involves soaking rolled oats in water, blending the mixture, and then straining out the solids. The critical step that distinguishes commercial oat milk from blending oats and water at home is enzymatic treatment with amylase. Amylase breaks down the oat starch chains into shorter maltose and glucose molecules. This is what gives commercial oat milk its characteristic natural sweetness (no sugar is added; the sweetness comes from the amylase-generated simple sugars) and its smooth, slightly viscous texture.

The same enzymatic process that makes oat milk taste good is responsible for its relatively high glycaemic index (GI). The GI of oat milk is approximately 69, compared to 27 for dairy cow's milk, 44 for soy milk, and 25 for unsweetened almond milk. For most healthy adults, this difference has minimal practical significance in the context of a mixed meal (where other foods slow glucose absorption). For people with type 2 diabetes, pre-diabetes, or insulin resistance, however, oat milk can produce a notably sharper blood glucose spike than dairy milk or most other plant milks, particularly when consumed in large quantities on an empty stomach (for example, in a large latte as a breakfast replacement). Soy milk is the more appropriate choice for people in this group who want a plant-based milk with a lower glycaemic impact.

The other key production variable is the addition of oil (usually rapeseed or sunflower oil), which provides fat for creaminess and helps with frothing in barista formulations. Standard oat milk contains 1.0–1.5g of fat per 100ml. Barista formulations typically contain 2–3g of fat per 100ml. Stabilisers such as gellan gum, dipotassium phosphate, and sunflower lecithin are added to prevent separation and improve performance under steam heating in coffee equipment.

Barista Oat Milk: The Category Where Brand Differences Matter Most

The barista segment is where the technical differences between brands are largest and most consequential for the end result in a cup.

Oatly Barista Edition

Oatly Barista is the product that catalysed the commercial oat milk boom, largely because it was the first oat milk to froth and texture reliably under professional steam wands. It contains 3g of fat per 100ml, dipotassium phosphate as an acidity buffer (which prevents the splitting that occurs when low-pH espresso is added to uncalcified plant milk), and rapeseed oil for richness. The frothed milk produces a microfoam that, while not identical to dairy in bubble structure, is close enough to use for latte art. It has a slightly sweet, clean oat flavour that complements espresso without competing with it. Price: approximately $4.99 per litre in the United States, £1.90 per litre in the UK.

The weakness of Oatly Barista is its sweetness, which some coffee professionals find masks the nuances of high-quality single-origin espresso. For specialty coffee, this is a genuine complaint; for most everyday café drinkers, it is not a meaningful issue.

Minor Figures Oat M*lk

Minor Figures is a London-based specialty coffee brand that developed its oat milk specifically for use in third-wave coffee shops where delicate flavour preservation is a priority. The formulation uses less added oil than Oatly Barista and achieves a cleaner, less sweet flavour profile that many baristas prefer for single-origin espresso and filter coffee applications. It froths comparably to Oatly Barista under a professional steam wand and holds latte art for slightly longer in some baristas' experience (likely due to the formulation's different stabiliser balance). Price: approximately £2.50 per litre in the UK, slightly higher than Oatly.

Minor Figures is not as widely available as Oatly in retail settings, being distributed primarily through coffee shop wholesale channels, but it is increasingly stocked by Waitrose, Sainsbury's, and Whole Foods UK.

Califia Farms Oat Barista Blend

Califia is a California-based plant milk brand that launched its Oat Barista blend in 2019. Compared to Oatly Barista, it has a lower sugar content (0.8g per 100ml vs Oatly's 4.4g) due to a different enzymatic processing approach that produces less complete starch-to-sugar conversion. The result is a less sweet oat milk that suits cold brew and iced coffee applications particularly well, where the sweetness of Oatly can become cloying. For hot espresso applications, some users find Califia slightly thinner in texture. Price: approximately $5.49 per litre in the United States.

Oat Milk for Everyday Drinking and Cereal

Outside the barista context, the priorities shift toward flavour, price, and nutritional profile for drinking straight and using in cereal, tea, and cooking.

Oatly Whole (Blue Carton) is the most popular everyday oat milk in the UK and Sweden. It has a full, slightly sweet flavour and the smooth texture that made Oatly the category leader. At approximately £1.70 per litre in UK supermarkets, it is competitively priced but not the cheapest option.

Alpro Oat Barista (and Alpro Original Oat) is the most consistently available mass-market oat milk across UK and European supermarkets. Alpro is a subsidiary of Danone, with the distribution infrastructure to stock most major supermarket chains reliably. The Barista formulation is widely used in mid-market coffee chains across the UK. The flavour is slightly more neutral and less characterful than Oatly, which is actually an advantage in mild-flavoured applications like porridge, cream sauces, and tea.

M&S Oat Drink (Marks and Spencer, UK) has earned a strong following as a house-brand challenger. At approximately £1.20 per litre, it is significantly cheaper than branded alternatives and performs well in both hot and cold applications. Taste tests consistently rank it close to Oatly Original in blind comparisons.

ALDI and Lidl own-brands are the cheapest readily available options in the UK, typically priced at £0.79 to £0.99 per litre. The formulations are functional and nutritionally comparable to branded products; the flavour is slightly less refined, but for use in cooking and baking, the difference is negligible.

Nutritional Comparison Per 100ml

The nutritional differences between oat milk brands and between oat milk and dairy are worth understanding clearly:

• Protein: 0.5–1.0g per 100ml for most oat milks, compared to 3.4g for dairy whole milk. Oat milk is a poor protein source relative to dairy and should not be relied upon as a protein equivalent.
• Calcium: Most commercial oat milks are fortified with calcium carbonate to 120mg per 100ml, matching or slightly exceeding dairy milk's 115–120mg. Check the label; some budget brands do not fortify.
• Fat: 1.0–1.5g for standard formulations, 2.0–3.0g for barista versions, compared to 3.6g for dairy whole milk.
• Fibre: 0.5–1.0g per 100ml, a genuinely unique advantage of oat milk among plant milks. Dairy milk contains no fibre. The fibre in oat milk is beta-glucan, the same soluble fibre that gives whole oats their cholesterol-lowering properties, though at the quantities present in oat milk the effect is modest.
• Sugar: 3.5–5.0g per 100ml for standard oat milks (all from enzymatic starch conversion, not added sugar), compared to 4.7g for dairy milk (from lactose).

Sustainability: Where Oat Milk Genuinely Excels

Oat milk's environmental credentials are well supported by life cycle assessment data. A 2018 Oxford University study by Poore and Nemecek, published in Science, found that oat milk production uses approximately 80 percent less land than dairy milk, produces 70 percent less greenhouse gas emissions, and uses 60 percent less water per litre. Compared to almond milk specifically, oat milk uses approximately 80 percent less water (almond cultivation in California's Central Valley is heavily irrigated and has been linked to groundwater depletion). Oats are predominantly grown in temperate northern climates (Sweden, Finland, the UK, Canada) where rainfall is sufficient and irrigation is minimal.

The sustainability advantage of oat milk over dairy is genuine and large. The advantage over soy milk is smaller and more context-dependent: soy milk has a slightly lower carbon footprint per litre in some analyses, though concerns about soy cultivation's role in deforestation in South America apply primarily to feed-grade soy destined for livestock, not to the food-grade soy used in soy milk production (which is predominantly grown in the United States and Canada under different land-use conditions).

The Verdict by Use Case

For espresso-based coffee drinks: Oatly Barista (widest availability, reliable froth) or Minor Figures (cleaner flavour, preferred by specialty coffee professionals). For cold brew and iced coffee: Califia Oat Barista. For everyday drinking, cereal, and tea: Oatly Whole, M&S Own Brand (UK best value), or Alpro Original. For baking and cooking: Oatly Full Fat (for richness) or any own-brand formulation where cost is a priority. For people managing blood glucose: soy milk is a more appropriate choice than oat milk; if oat milk is preferred, Califia's lower-sugar version is the best option within the category.

Related: Dairy-Free Cooking: How to Replace Butter, Milk, and Cream | Plant-Based Milks Compared: Nutrition, Taste, and Sustainability