I have my friend to thank for this. She had gotten herself a Hario and was telling me about how her cold coffee tasted. The Hario that she got was actually used to make cold immersion coffee where you pour cold water into coffee grounds and keep it in the fridge for 8 to 24 hours. I was quite sure that was not what I understood to be true cold brew coffee. I thought proper cold brew coffee should be cold drip coffee. I then decided to look for a way to make it the DIY way. I came across this in my search. Towards the bottom of the article, it talks about DIY cold drip coffee. Feeling quite pleased that some people used an Aeropress, plastic water bottle and cold water, I thought I would attempt it as well.
I did not want to use a disposable plastic waterbottle with a pricked hole in the cover, so I decided to use a proper waterbottle instead. In my first attempt, I used a 750ml sports waterbottle but that attempt was a complete failure as I did not take into consideration the vacuum effect which eventually stopped the water from dripping. Duh!
So I decided to cut open the bottom of another unused water bottle to pour my cold water into. I then adjusted the spout of the waterbottle to a reasonable drip rate. These are the steps I took but you may follow the link I posted earlier as well.
1.Wet the paper filter for the aeropress, put it into the cap and screw that onto the main holder of the aeropress.
I used a ratio of 1:8 for my coffee grinds and water. When the coffee powder reached reading no. 1 on the aeropress, I then leveled out the powder and placed a second piece of filter on top of the coffee powder. This is important as it prevents the coffee powder from splashing up when the water is dripped in. In the last picture below, bits of coffee powder got splashed up onto the sides. The filter also evens out the flow of water from the drip so that it covers more areas instead of only one part.
2. Pour in 500 ml of cold water into the waterbottle, which is the estimated 1:8 ratio. Cover the waterbottle so that the cold will last a little longer. Make sure the spout is closed when you pour in your water.
3. Adjust the spout such that the drip rate is about 45 drips to 1 minute. This was not easy to do as either too much or too little water came out. You can adjust the spout over the coffee powder or over the sink. If you adjust over the coffee powder, you can use the initial water that comes out to wet the powder. Be careful that you do NOT put in so much water until the coffee starts to drip out from the bottom. Just have enough water to wet the powder but not to start the drip yet. This helps to bring out the flavour of the coffee a little more evenly. If you think the coffee powder is already wet enough but you have not been able to get a decent drip rate, move the waterbottle over a glass bottle and adjust the drip rate. Once you are happy with a drip rate of 1 drip every 1-3 seconds or 45 drips to 1 minute, then move it back over the coffee powder. Or if you want to leave the coffee powder to saturate a little longer, then let the water drip into the glass for a while first. You can always pour the water back into the bottle when you are ready to start dripping into your coffee. I found that leaving the coffee saturated for 5 to 10 minutes before the dripping actually starts going through to the collection bottle below made the coffee taste better. Here is an article on cold blooming the coffee powder. I thought blooming required water at higher temperatures but perhaps it is not always necessary.
4. When you are happy with the drip rate, you can then leave it to drip for a few hours. I have not timed how long it would take to finish dripping. But do check the drip occasionally to ensure that it does not stop dripping.
The early part of the dripped coffee will be much stronger than the latter part. So if you are going to pilfer the early parts, don’t take the whole lot cos those who drink the latter parts will find that the coffee may not be strong enough. Best to leave the whole thing to drip until it is done and then mix the dripped coffee up before serving.
What I did not do:
- I did not measure the temperature of the water for the dripping. I basically used cold water with some ice cubes in it.
- I could not control the drip rate very well. I have ranged from 1 drop every 8 seconds (yawn!) to a slow trickle which I had to immediately shut off and retry. This was when I first tried it and I used that to saturate the powder so it turned out fine.
- I do not roast or grind my own coffee. I used an organic medium roast for this.
P.S. There is a small device called PuckPuck made by a UK creative design company that is used with the Aeropress to make cold drip coffee easier. You can find out more about it here. A frustrating part of this process is adjusting the consistency of the drip and this little device may just solve that problem. (This publicity is free. I was not paid nor given anything for it.)