What impact does different milks have?

What impact does different milks have?

The word “milk” is not just reserved for the stuff that comes from mammals. Plant milks have been around for centuries in one form or other, and almost all cultures refer to them as milk. Calling plant-derived juices or fluids ‘milk’, is at least 1000 years old.

“Linguistically speaking, using ‘milk’ to refer to the ‘the white juice of certain plants’ (the second definition of milk in the Oxford American Dictionary) has a history that dates back centuries,” the Smithsonian notes. “The Latin root word of lettuce is ‘lact’, as in lactate, for its milky juice, which indicates that even the Romans had a fluid definition for milk.”
- Smithsonianmag

Soy milk has its roots in China but has been around for well over 100 years in Europe and of course, is now commonplace in most countries.  Almond milk is regularly included in Egyptian recipes dating back from the 13th century but rapidly found its way to India and Europe by the 18th century. Now, of course, you will find almond milk in every influencers’ morning green smoothie routine.

Plant milks have flowed back into fashion in the last decade and continue to grow in popularity with sales topping $20 billion USD in 2020. The overwhelming reason for this trend is the concern that the dairy industry is causing harm to our environment. 

Often though, our solutions can be worse than the problems we are trying to solve. Environmental problems are complex – with palm oil being an excellent example of this. Sometimes boycotting one ingredient will cause greater harm by putting more pressure on a different resource that is perhaps not as efficient.

So, if you want to make the switch, which milk has the lowest environmental impact and which one is the best substitute for dairy?

Well, it depends on what you are trying to do.

If you are looking at overall, the quick answer is oat milk. Oat milk requires the least amount of water and land to produce. The worst, by contrast, is dairy which uses more land, water and fertilizer and produces more carbon emissions than any other option. By a significant margin. To produce one litre of dairy milk, we need 1070 litres of water. 

If carbon emissions are your main concern, almond milk is your best bet, though oat is not a slouch there either. For dairy, it can be as high as 4.5kg of carbon emissions for one litre of milk. This is one metric that varies depending on location as some countries are able to farm cows with an overall lower footprint – New Zealand has one of the lowest carbon footprints per cow, for example.

But there is a caveat here. The number of life cycle analyses (LCA) done on plant milk alternatives are low so this is an area of ongoing research. As with all science, conclusions may change slightly based on future research (which is the whole point of scientific research!).

Because these things are always easier to understand visually, here is a table, comparing various milks and their impact.

*Does not include deforestation that may be involved (see under soy milk below for more info.)

But like everything, that is not the end of the story. Every other alternative has a downside too.

Almond milk:

Almond milk has an enormous thirst and ironically, grows preferentially in areas facing drought conditions (like California). It is one of the trendy alternatives at the moment, but studies have shown that the percentage of actual almond in your almond milk, can equate to as little as 3%. Because of this, the nutritional benefit is… negligible.

Perhaps you are better off using tap water in your smoothie and simply adding in a couple of almonds instead. Or, make your own home-made almond milk.

The other big issue facing almond milk is bees. Bees have to be drafted in and carted around to pollinate the almond trees, yet over a third of them die each season. This is a complicated issue and not limited to almonds – enormous areas of monoculture are wreaking havoc on all our insects.

Oat milk:

Oat milk is the best option across the board, based on the data we have available. It’s also nice and creamy and is my favourite in a coffee. Thankfully, oat milk is becoming much more widely available. Its carbon emissions aren’t the lowest, but Oatly – the largest producer of oat milk in the world has put significant efforts into lowering their carbon footprint and have had it independently measured at just 0.34kg/L. So, there is hope for its improvement.

Rice Milk:

Renowned as the ‘water guzzler’, rice milk requires a lot of water per litre. It also has pretty slender nutritional benefits and produces the highest carbon emissions of any plant milk. Rice paddies are also bacterial soups favoured by methanogens (bacteria that produce methane – a potent greenhouse gas) and they use a good chunk of fertiliser too. Not as bad as dairy, but far from the perfect option.

Macadamia milk:

For those without nut allergies, macadamia is apparently the closest to dairy milk in texture and taste. I haven’t tried it so cannot comment, but it certainly sounds delicious. As it’s a newcomer, it has no LCA studies that I can find, so I haven’t included it in the table above and as such its footprint isn’t yet known. As it is a nut that grows in similar areas (though with a greater geographical spread), you can assume it would have similar properties to almond.

Soy milk:

Soy milk is a great option, but there is a massive caveat there. You need to ensure the soybeans used to make your milk are sourced local, or at least, not from Brazil. Enormous chunks of the Amazon are being deforested every day for soy plantations. It’s worth nothing that almost 90% of soy grown is for animal feed, but if these beans are used to make soy milk, it will massively increase the carbon footprint and directly support the destruction of critically important ancient rainforest.

Hemp milk:

Hemp is revered as the wonder crop that will solve almost all our issues, from climate change to compostable plastic and now to milk (spoiler alert: most claims are very overblown). At present, it’s still quite niche and has no LCAs that are really robust enough to rely on. But as it’s grown in small amounts usually by companies and people very passionate about the environment, its footprint is considered one of the best. We just don’t know that for sure yet.

Coconut milk:

There is a reason we have a direct relationship with our coconut oil producers… the industry is rife with despicable practices, environmental degradation and even (and I promise this is true...) monkey enslavement. Coconut milk is of course most commonly used for cooking, but there are now more dilute options available for drinking and for use in tea and coffee. It’s also quite late to the plant milk race so again, limited information available, but it’s safe to say that if sourced sustainably and fairly, it would be a relatively low impact option.

Summary:

The worst environmental option: Dairy milk - regardless of how sustainably and efficiently produced, it is always the worst option for the environment when compared to plant milks.

The best environmental option: Oat milk – Based off current scientific research, oat milk is the clear winner across the board though it does lose out to almond for carbon emissions and rice milk for land use.

However, there is no perfect option when it comes to environmental decisions and your preference for taste and froth (is that the official barista terminology?) also matters. If you don’t like oat milk, try another. There are many, many plant milk options out there including recipes for making home-made milk that I would encourage you to look into.

Resources:

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Bray, H., & Ankeny, R. A. (2019, October 27). Crying over plant-based milk: Neither science nor history favours a dairy monopoly. Retrieved August 21, 2020, from theconversation.com

Berry, S. (2015, November 09). The unhealthy truth about almond milk. Retrieved August 21, 2020, from smh.com.au

Soybeans. (2015, October 9). Retrieved August 21, 2020, from ucsusa.org

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Soy Agriculture. (n.d.). Retrieved August 21, 2020, from globalforestatlas.yale.edu

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Annette McGivney in Flagstaff, A. (2020, January 08). 'Like sending bees to war': The deadly truth behind your almond milk obsession. Retrieved August 21, 2020, from theguardian.com

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