Flash brew, also known as iced pour over, is a fast and creative alternative to traditional cold brew that allows you to prepare chill and refreshing iced coffee for a group, or just for you, at a moment's notice.
While true cold brew, made with brewers like the Hario Mizudashi, takes 12-14 hours in the fridge for proper flavor extraction, the flash brew method utilizes fresh coffee, a pourover coffee maker, and ice to create a cold coffee beverage in under ten minutes.
This recipe will cover brewing iced pour over coffee for a small group using the Chemex, but can be replicated for other pour over methods and volumes by following the same coffee to water ratio and brewing fundamentals.
Recommended Coffee to Water Ratio: 1:17 (light and refreshing)
What you'll need
- Chemex brewer
- Chemex filters
- Fresh coffee, medium-coarse grind (40g)
- Scale
- Timer (if scale does not have built in)
- Gooseneck kettle / hot water (390g) just off boil at 205°
- Ice (290 g)
Prep
- For this recipe, 40% of our water comes from the ice itself. Add your ice cubes (290g) to the bottom of the Chemex.
- Fold your Chemex filter into a cone and insert into the brewer, with 3 layers on the spout side. Do not pre-rinse your filter.
- Grind the coffee of your choice on a medium-coarse setting (about the center point on most grinders). Place the grounds in your filter, tapping or lightly shaking to level the grounds. Note that for this recipe we are using a 1:17 brew ratio: 40g coffee and 390g hot water + 290g ice (680g total of final brew). Scale up or down depending on the size of your Chemex and how many cups you want to brew.
- Place your brewer on a scale and tare to 0.
Brew
1. Start your timer and pour 90g of hot water into the center of the grounds to start the bloom. Then add the remaining water in three even pours as follows:
- At :45, pour 100g of water starting in the center of the grounds, circling outward, then inward, with intentional and slow movements, making sure to saturate all of the coffee. Don't pour water onto the edge of the cone—you just want to evenly saturate the grounds bed (total weight at this point is 190g)
- At 2:00, pour 100g more water (total weight 290g)
- At 3:00, pour remaining 100g (final weight is 390g)
2. Serve coffee once the filter stops dripping, which should happen between 4-5 min.
3. Discard the coffee grounds and filter directly into your compost.
Pro Tips
- Depending on your preference, you can serve this coffee with additional ice in the glass for an even cooler and more refreshing sipping experience.
- Pay attention to the flow rate of your chemex as you brew. If the water appears to be gushing through the filter as you brew, it is likely that the coffee was ground too coarse. If it's hardly dripping, or if the total brew took longer than 5:00 minutes, try a coarser grind next time.
- Due to the lower volume of hot water than a standard Chemex brew, the flash brew method requires us to make our pours slower and more methodical, spaced out over greater time intervals.
- If you are recreating this flash brew method for another pourover dripper, like the Hario V60 or Origami, be sure to brew into a range server or other suitable coffee carafe as you normally would, prefilled with the appropriate quantity of ice.