But I am a connoisseur of porridge, which implicitly makes me an authority on oat milk, and this Christmas my household bought an oat-milk-making machine.
Making oat milk isn’t rocket science: whizz up some oats in some water (with some nuts and dates to provide some fat and sugar) and strain through a very fine mesh. (And then find a way to eat the pulp left behind because you abhor waste and fibre is good for you.)
We tried this using non-specialist kit (blender and muslin) and it was too fiddly to do on a regular basis (the straining is inefficient and cleaning the muslin is a pain), so we carried on buying cartons of oat milk. But, with a specialist machine (and a bit of practice), you can make a litre of oat milk in the time it takes your tea to brew — which for me makes home-made oat-milk a realistic prospect. (The machine is just very good at doing the whizzing and straining all at once and being easy to clean.)
But was the oat-milk machine really a good deal financially and environmentally? (TL:DR: yes, but only if you make more than about 200 litres.)
Why oat-milk? A quick carbon-footprint reminder
Mike Berners-Lee’s handy, thoughtful, anti-greenwash How Bad are Bananas? The Carbon Footprint of Everything (now in a second, revised edition, but I’m still using the first, 2011 edition) estimates the following carbon footprints for different kinds of milk (at the point when they’re consumed):
|type of milk||CO2-equivalent per litre|
|UK cows’ milk||2kg|
(Minor Figures, whose oat-milk we previously bought, claim to be carbon-neutral because they pay for offsetting; but they quietly admit in the small print that this ‘offsetting’ doesn’t change the fact that the carbon they’ve emitted is not actually going to get put back in the ground. Meanwhile, their website lists lots of pointless factoids, but nothing you could use to guess at their carbon emissions per litre sold. They’re probably nice people, but their products are in no meaningful sense carbon-neutral: I’m sticking with Berners-Lee’s 0.9kg estimate.)
It’s obvious that oat-milk is a much better deal than cows’ milk in terms of greenhouse gas emissions. Other measures position it as much better in terms of water-footprint and land-use too. And nutritionally it’s not that different from cows’ milk [edit: the rest of my household opines it’s not that similar either; I was just surprised that they weren’t more different. Follow the link and check the facts 🙂 ].
But would oat-milk made in a domestic oat-milk machine cut the carbon footprint enough to make up for the carbon footprint (and kitchen clutter) of the machine itself?
20-30p per litre, breaking even after 110-270 litres
It’s at least easy to work out whether the machine is cost-effective — and cost is one proxy for carbon footprint (extremely rough, but, since the costs of goods to a significant extent reflect energy consumption, not useless). There might be lots of similar machines out there and I don’t have views on which is best, but we got an Almond Cow for an undeniably painful £188.40 (including about £10 postage).
Judging from the last quarter, my household of two consumes 40 litres of oat milk per year (mostly in tea: we don’t eat breakfast cereal). (If you can only think of milk in pints, a pint is roughly half a litre.) Buying fancy oat-milk, we pay £2 per litre, so that would be £80 per year. (It would be £1 per litre if we got the normal oat-milk from Tescos; remarkably, we think our own stuff competes with the posh stuff on quality. Maybe we’re kidding ourselves, but hey, whatever works.)
Making oat-milk is much cheaper than buying it. The cost of the tapwater and energy used is negligible. We use up to 100g of oats per litre of oat milk, so let’s call that 4kg oats per year. Buying organic oats in bulk, that would be about £8 (£4 if we got normal oats). Accounting for small but pricier quantities of dates and hazelnuts, the annual cost of ingredients is about £12 (30p per litre). So we’ll save about £68 per year, or £1.70 per litre. (We’d only be saving 70p if we bought the cheap oat-milk though.) So the machine will pay for itself after about 110 litres or about three years. Assuming it doesn’t break down before we make our hundred and eleventh litre (or two hundred and seventieth if you’d normally buy the cheap oat-milk), it’s financially a good deal.
100g CO2-eq per litre, breaking even after 200 litres
The almond cow website says a bit about how many tetrapacks you don’t use up if you make your own oat milk, which is a good point; but, feebly, they attempt no carbon-footprint calculations.
Luckily, How Bad are Bananas? covers the carbon footprint of porridge oats as well as oat-milk: 80g CO2-equivalent per 100g. Again, the carbon footprint of the water and energy is negligible. I’m not sure about the dates and hazelnuts, but they are few, and they aren’t air-freighted or very heavy, so it can’t be massive.
So, very roughly, a litre of oat-milk from my oat-milk gadget has a carbon footprint of maybe 100g instead of maybe 900g. This is easy to believe because selling oat-milk commercially basically involves driving a product that is 90% water around in diesel lorries. (Shout-out to The Modern Milkman: they deliver the stuff under electric power in glass bottles that they reuse, so might compete slightly better with my home-made oat-milk?) How Bad are Bananas? is very clear that we should assume large margins of error, but since there’s nearly an order of magnitude between the carbon footprints of the home-made oat-milk and the shop stuff, we can be confident that the home-made stuff is a good deal environmentally.
I have much less to go on to work out the carbon footprint of the oat-milk machine itself, but Berners-Lee gives one rule of thumb for domestic appliances: 0.66 kg CO2-equivalent per USD expenditure on domestic appliances (at 2008 prices). A lot will have changed since 2008, but let’s say on this basis that the manufacture of my (surely overpriced?!) $239.61 Almond Cow led to 158kg CO2-equivalent in greenhouse gas emissions.
And let’s say that with every litre of oat-milk I make I really am saving 800g CO2-equivalent. If so, my Almond Cow will become carbon-neutral after 198 litres. This is respectably near the middle of the range of the Almond Cow’s financial break-even points; thus two different estimates of its carbon-neutral point (albeit both ultimately drawing on price data) look broadly consistent with one other.
The efficiency of my oat-milk-making gadget will enable me to switch from buying oat milk to making it, and I’m confident that, given our usually expensive taste in oat milk, I’ll be saving money after 110 litres (195 pints). Almond Cow ought to get their act together and publish properly researched figures for the environmental footprint of their product, but I think it’s plausible that as long as the machine keeps working, it will be reducing my carbon footprint after around 200 litres (350 pints) — and the longer it keeps working, the better a deal it is. Rather than drinking oat-milk with half the carbon footprint of cows’ milk, I’ll be drinking oat milk with more like one twentieth of the carbon footprint of cows’ milk.
Using the oat-milk-machine definitely isn’t going to save the planet, and if people buy them but don’t use them, or if they turn out not to be built to last, they are terrible news. But in my case, the machine will slightly reduce my carbon footprint, and will do so more convincingly than buying Minor Figures’s not-really-carbon-neutral tetrapacked oat-milk.