Cold Matter 001 - Cold Brewing Explained

Written by Pat

What is cold brew?

Cold brewing is a method of brewing tea and coffee without the use of heat as a catalyst for extraction. This is how it differs from iced tea and ice coffees, those products are made using hot water and it is later cooled down whereas ‘cold brew’ are kept cold the entire process. Cold brewing was popularised in Kyoto, Japan, as they believed the use of hot water was damaging to the tea leaves and resulted in unwanted bitter flavours.

How is it made? How difficult would it be for a newbie to brew their own?

Cold brew tea and coffee are essentially made the same way, both use cold water to brew. The lower water temperature increases the brew time significantly but produces a less bitter taste. To make cold brew, you don’t need to be a barista or tea sommelier. If you can make a cup of tea or instant coffee then you have more than enough experience to start your own batch of cold brew. 

What are the different methods?

The most popular method for cold brewing tea and coffee is steeping. The tea leaves (or ground coffee) are left to steep in cold water for hours. The time will depend on the desired quantity being produced, the raw ingredients and the desired taste. This can range from 6-24 hours. This method will generally produce a concentrate, but can be consumed without being diluted

Another method for cold brewing is dripping in which cold water is dripped over tea leaves or ground coffee. This method is quicker than steeping as the raw ingredients only react with a small volume of water just on a more frequent basis, that is literally drip by drip. The brew time is shorter when compared to steeping but is also dependent on the volume being produced.

What ingredients and tools do I need?

To get started on your first batch of cold brew, all you need is a bag of tea or coffee, some water, and a decided method of extraction.

In regard to the equipment required, it is best to visit  your local specialty coffee shop or roaster, as many of these locations sell dedicated brewing equipment. Otherwise, many department stores carry a lot of coffee and tea brewing equipment. Steeping equipment is often cheaper and easier to use but for enthusiasts dripping can really be a fun experience that enables you to develop your own style and really perfect your craft.

Some other useful tools for cold brewing are:

  • Scales to weight out raw ingredients
  • Measuring jugs for water
  • Coffee grinder as fresh ground coffee is best
  • Strainers or filters

How should I store my cold brew once its finished? How long will it last?

Once your brew has finished, it is best consumed within 1-2 weeks if kept refrigerated. Any longer can result in a loss of flavour, but is still safe to drink

Is there anyone who shouldn’t drink cold brew?

Cold brewing does result in a higher extraction of caffeine. This would be best avoided by those with caffeine sensitivity, underlying medical conditions, pregnant women, or children. For people who cannot consume high quantities of caffeine, there are decaffeinated alternatives that will still work well.

Is there a way I can flavour my cold brew, or is it best left untouched?

A lot of people enjoy drinking their undiluted cold brew over ice, but you can add some some water, milk or milk substitute if you prefer a less intense flavour. For cold brew tea, many people like to introduce some sweeter flavours by steeping it with fresh fruits such as lemon and peach.

How much cold brew should I drink in one day?

Since cold brew does have a high caffeine content, it is best to limit your daily serving depending on the individual’s caffeine tolerance. A typical serving of straight cold brew coffee (330ml) can contain between 250mg and 300mg of caffeine, depending on the type of coffee used. Cold brew tea generally contains less caffeine, and a 330ml serve usually yields around 100mg. Most adults can safely consume around 400mg of caffeine per day, so it is recommended to stick to one bottle of cold brew and 3-4 bottles of tea at a maximum.