Cold Brewed Coffee

I must first apologise for the lack of technical blogs recently, but real life has interesting bits in it at the moment.

As I mentioned earlier this year, life has been utter chaos and I have been drinking more and more caffeinated soft drinks. When I started seeing a litre’s-worth of cans on my desk each day, I decided it might not be as healthy as I might like — and it was costing a fortune too, so cold coffee it is!! I have tried cold coffee before and it tastes… well like coffee you have made then put in fridge. It has a nasty bitter aftertaste: perhaps I was just making it wrong?

Turns out there is this thing called “cold-brewed coffee.” I’ve had seen it online obviously, and it’s typically made in £40+ Kickstarter coffee pots then served in handcrafted mason jars… Meh. I dismissed as an over-priced fad.

Thankfully it turns out that large parts of the world have been making it for ages, and I could get a Japanese single litre glass pot that fits in the fridge door for a far more sane £17.

It turns out that pre-ground coffee is not suitable, after a period of suspicion I discovered that this is indeed correct: you get a lot of grit at the bottom of the pot with pre-ground coffee, <sigh> so how much is a fecking coffee grinder? Well about £9.50, and approximately 10 minutes of one’s time to prep. enough coffee for the week. That is bearable (ohh and un-ground coffee is a bit cheaper that ground, on a brand-by-brand basis). Sold!

You are supposed to use filtered water AS WELL (this is starting to sound like stone soup). Well, I drink London water so I can see their point there,. “But I’m not buying a water filter!” says I… Hang on, didn’t we get one when they had one of those “buy one cartridge get 10 free + plus the jug” deals a while back? <rummages in a back cupboard> Bingo! OK, we have filtered water. For more filters, Robert Dyas always has sales on.

Let’s finally make the stuff. It seems you use 80 grams of rough ground coffee for a litre (8 normal coffee spoons), pouring the water slowly over the coffee in a spiral just like with a normal filter coffee. Give it a good stir and pop it in the fridge for at least eight hours before attempting to drink (I have found a simple 24 hours works best). I wash out the filter and make the next batch as I put today’s in the thermos.

I normally have my coffee with lots of sugar and milk but found I did not need the milk at all as the coffee is far less bitter. The sugar on the other hand was a small pain as it obviously does not dissolve well in cold coffee, so I now make a batch of sugar syrup and keep it in the fridge with the coffee. I make the syrup like so:

Sugar syrup

  1. Put 1 cup of water in a pan.
  2. Add 1 cup of sugar
  3. Bring to boil while stirring until all the sugar has dissolved (it will go clear).
  4. Take straight off the stove as soon as it boils, cool it then bung it in the fridge.

Apparently sugar syrup lasts up to a month in the fridge so there is no worry there.

How does it all taste after this faff? It tastes really, really good — clean and fresh and just what I wanted as a replacement to an energy soda. Obviously you need to use a thermos to keep it cool. I use Chillys water bottles which work perfectly. Whilst I was initially worried about the coffee tainting the water bottle so I would no longer be able to use it for normal water, turns out the cold coffee doesn’t seem to do that as much as hot coffee. Even if there was some taint, a tablespoon of bicarbonate of soda filled up with water overnight seems to remove any remaining taste.

Total costs:


Coffee filter: £17

Coffee Grinder: £9

Water Filter Jug: £20 (I already had one)

Thermos or Chillys water bottle: £20 (I already had one)

total: £56

Running Costs

Coffee: A 1kg pack of good coffee beans costs about £13, 1 litre of coffee takes 80g, so a week is about a fiver.

Water Filters: £36 for 12 months (according to Robert Dyas) so a week is less than a pound.

Sugar: I go through 2 cups of sugar a week, i.e. 400 grams, so about 25 pence

total per week: £6.41 (let’s say £6.50 with a bit for electricity and water)

Conclusion Energy drinks were costing me £4 – £5 per day, so we are onto a winner after about 3.5 weeks. Nice!

An added benefit, that appeared later, is that too many soft drinks were making me cough! I had a nagging and persistent cough for about 6 months, and just thought it was a left-over from a chest infection, and that I would deal with it when I had time. Turns out a week after I moved to cold-brewed coffee it just packed in. When I switched back to soft drinks for a few days it returned. Well OK then: coffee is here to stay.

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