The Ultimate Guide to Alternative Milks for Coffee

We all remember the Oatly shortage of 2018, if you were a café owner and used it as a milk alternative you will remember the pain of trying to locate a few crates for exorbitant prices. Dairy milk alternatives are becoming hugely popular due to a combination of eco-conscious consumerism and the rise of lactose intolerance. Dairy products aren't unhealthy, and you don't need to cut them out if you enjoy them — not only is cows' milk an excellent source of calcium, protein, and vitamin D, it's also more hydrating than water according to a new study by St Andrews University in Scotland. 

Although vegan milks are way more sustainable than cow’s milk, there’s a stark difference between the eco-friendliness of the different nut and plant based milks available. Also one has to keep in mind your location, is it really more environmentally friendly to be drinking milk imported from California or Sweden when Ireland has a huge milk production industry in your own back garden?

Dairy Milk

It’s no secret that cows release high levels of methane, a strong greenhouse gas. The dairy industry has one of the highest carbon footprints in any sector, with cow’s milk having an impact three times the size of any other milk alternative.

A recent FAO report has highlighted that the average carbon footprint of global milk is 2.5 kg of CO2e for each litre of fat and protein corrected milk produced. The corresponding figure for Ireland is about 1 kg of CO2e per litre of fat and protein corrected milk, when carbon sequestration is included. To put that into perspective, a kg of CO2e will charge a smartphone 128 times.

So, we compared dairy alternatives to find out how eco-friendly they are. The environmental impact statistics are sourced from a recent University of Oxford study, unless specified otherwise. For uniformity, all measures of glasses are 200ml.

Soy Milk

The original dairy alternative, soy milk has taken a backseat with the rise of newer, trendier vegan milks. However, it remains one of the most water-friendly plant-based milks, with only 5.6l water required to produce a glass of soy milk.

The carbon emissions of soy milk amount to 0.195kg of CO₂e per glass, which is marginally higher than oat and almond milk. Soybean cultivation requires 0.14 sq m of land per glass, and has become a major cause of deforestation in the Amazon rainforest. However, only about 10 per cent of soybeans are used for milking purposes, with the rest being used for animal feeding and oil production.

Almond Milk

While it may be the most popular milk alternative now, almond milk has some negative connotations for the environment. A glass of almond milk needs 74l of water for production, which is by far the highest amount of water for a non-dairy milk.

But its greenhouse gas emissions are amongst the lowest, at 0.14kg CO₂e per glass. Almonds also require little land for the same amount of milk, at 0.1 sq m.

These positive still don’t balance out the heavy use of water, which is a major issue considering that over 80 per cent of almonds grow in California. The US state has seen many droughts and wildfires over the last few years, and the concentration of almond cultivation leads to increasing carbon footprints the farther you live from California.

Another issue is the honey bee, for many years the population in California has being dying off at an alarming rate, every year almond growers rent upwards of 1.5 million colonies of honeybees a year, at a cost of around $300 million. Without the bees, there would be no almonds, and there are nowhere near enough native bees to take up the task of pollinating the trees responsible for more than 80 percent of the world's almonds. The trouble was, bees and larvae were dying while in California, and nobody was sure exactly why. More recently, the culprit was found to be a toxic mix of insecticides and fungicides which individually were harmless to the bees, but when mixed together were responsible for killing up to 60% of larvae.

Oat Milk

Appearing in more and more cafes, oat milk finds a suitable balance in terms of its environmental impact. Its carbon emissions are low, at 0.18kg CO₂e per glass, while the land use is slightly higher than soy or almond milk, with 0.16 sq m of land needed to end up with one glass of oat milk.

Oats don’t require a lot of water for growth, only 9.6l per 200ml glass, and this alternative tends to be favoured by baristas, as its thick texture makes it ideal for steaming and foaming.

Coconut Milk

Coconut milk has quite a small environmental footprint, owing to the minimal use of water for growing coconuts. According to estimates, a 200ml glass of coconut milk only requires 0.5l of water, in stark contrast with other plant- and nut-based milks.

Coconut trees have the ability to filter out carbon dioxide, which helps fight greenhouse gases. However, since coconuts are usually grown in tropical areas, the transportation drives up the carbon footprint.

Hemp Milk

Touted as the most planet-friendly milk alternative, it’s a fairly recent addition. Hemp production needs relatively fewer pesticides and herbicides, and crops can filter out CO₂, taking in twice the amount it releases. Being a non-GMO (genetically modified organisms) plant, it does not reduce the soil’s nutritional content.

Help cultivation does require more water than oats or soybeans, but on the flip side, there’s very less wastage as most of the plant is usable.

Macadamia Milk

Macadamia milk is the newest on this list, and the cheekily-named US-based company Milkadamia is leading the charge. Billed as a climate-friendly establishment, the macadamia nuts are grown with regenerative farming methods with minimal fertilisation and irrigation, and are free of GMOs.

The barista version of their milk is also palm-oil free, which reduces the environmental footprint considerably. However, as macadamia nuts are native to Australian rainforests, and the milk is processed in the US, the carbon emissions of Milkadamia rise due to transportation.

So how do dairy-free milk alternatives for barista professionals differ from other plant milks?

"Dairy milk fat naturally contains compounds with buffering properties. That's why it doesn't curdle as easily as plant-based products."

In alternative plant based milks specifically designed for baristas to use, the stability of proteins has been increased by buffers – carbonates, phosphates and citrates. These prevent a rapid change in pH when the plant drink comes in contact with acidic coffee. Plant milks also often contain added fat for nice flavour but also to protect proteins.

Stabilisers are also used commonly in plant milks for improved heat tolerance and structural homogeneity. Not all milks go with all types of coffee, however. Light roasts are often more challenging to pair with plant milks than dark roasts.

What to take into account when using plant milks instead of dairy milk?

Light roasts are far more acidic than dark roasts, but acidity of coffee is also affected by factors such as origin, cultivar, species and harvesting season. The heat tolerance (the amount of heat the milk can take before it curdles) can be improved by heating them slightly lower temperature to that of cows milk. At times the taste of plant milks may be a bit of a headache. Just like cow's milk, dairy-free milks also affect the flavour of the coffee drink.

Top Tip: Some people add a bit of cold plant milk to the coffee before combining it with the hot plant milk. This cools the coffee a little before it comes in contact with the hot milk.