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Immersion Cold Brew: Beginner's Guide

Cold brew coffee is one of the hottest trend in coffee, and it is here to stay.

But the idea of a cold cup of coffee could send people running for the hills if they are yet to try it. If done right, however, it could well result in one of the best home brewed coffees you have ever had – and there is opportunity to heat it up, too.

If you are serious about making cold brew, you will need a cold brew coffee maker and some suitable coffee beans or grounds

What Is Cold Brew?

Cold brew coffee is simply the method of brewing coffee in cold water rather than near boiling.

It is not to be confused with iced coffee, where espresso coffee is served over ice with the addition of milk and syrups.

But why brew the coffee in cold water? Well, first of all, the lack of heat treats the grounds better. Using hot water can scald the grounds, resulting in a slightly burnt and overdone taste. However, steeping in cold water for 24 hours or more allows the flavour to be captured without the negative aspects. This is what the ‘immersion’ part is.

This results in a concentrated coffee solution which you can then add extra water, milk and sugar to, as you would have an ordinary coffee. You can even heat it up in the microwave!

Best Cold Brew Coffee

Why Cold Brew?

  • It is simple. Just add the grounds to the filter basket, fill the jug with water and pop in the fridge for 6, 12, 24 or more hours
  • The coffee is always ‘there’ when you go to serve. Most immersion brewers will hold enough coffee for quite a few cups – some could even give you a week’s worth of morning coffee. Just pour, and prepare as you wish
  • There is a more mellow flavour. The extended brewing of coarser grounds in cooler water means a smoother, softer taste which will balance everything so there isn’t just one overruling flavour
  • It is ideal for anyone with an aversion to acidic drinks. Toddy Cold Brew system claims their cold brew can contain 67% less acid when compared to other methods. Great news for anybody with a sensitive digestive system


  • Some of the above could be seen as a negative. People can like an acidic, strong bitter taste to their coffee which is only achieved with hot water and ‘quicker’ methods
  • It can also mean complex flavours from speciality coffee aren’t discovered, such as floral, nutty or herbal tastes as they are all ‘balanced’ together
  • You need a very fine filter, or the coffee can become a tad ‘gritty’, which can also be an issue with the French Press (which is another immersion method)
  • The amount of preparation is high – you have to usually prep 6/12/24 hours ahead, so while a big serving can be made, that first cup could take a while to reach you

Which Grind Do I Need To Use For Cold Brew?

It is a good idea to have a coffee grinder to hand if you have speciality equipment such as this. A consistent grind is vital for a consistent good taste.

But the good news is that you don’t need a highly complicated, expensive one. It is best to stick with a coarse grind, which will make the filtration process easier and your coffee taste far less bitter.

Grinding your beans very fine, which takes longer, can heat up the grounds, which can negatively affect your cup as they could become burnt – not what you want for such a sensitive method.

A manual grinder at the budget end of the scale would probably be just fine as every grind wouldn’t have to be perfect, but invest in something more precise if you will be trying various methods.

Cold Brew Coffee Tips

  • Ensure that all grounds are saturated. If you measure out everything correctly, missing some of the grounds could result in a weaker brew. Don’t forget to stir them through before leaving, or add the grounds and water slowly in a layer technique
  • Choose your coffee wisely. We don’t mean ‘buy the most expensive starry bag’, but rather adapt it to your flavours and tastes of preference. A lighter roast will have more caffeine but fruity, floral flavour. Dark roasts have less caffeine but a bitter, woody smoky flavour generally
  • Find the perfect ratio for you. The standard is 15:1 (water to coffee) so 1 litre of coffee will require 67g of ground coffee. But a concentration you want to customise could require 10:1, or weaker coffee 18:1
  • Use high quality water. Filter it before hand if you wouldn’t personally drink your water straight out of the tap – remember that coffee is up to 99% water
  • Cold brew should ideally be stored for a maximum of 7 days, in the refrigerator. You may wish to buy an immersion cold brew maker which fits in the door of your fridge, but if not, keep the coffee in airtight containers