How to Brew Coffee with Cold Water? The Impact of Cold Water Brew Time on Flavor

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Previously, when making iced coffee, most methods involved Japanese iced pour-over, ice drip, or cold brew techniques, with relatively few people using ice water for pour-over. Today, FrontStreet Coffee aims to explore what the appropriate bloom time should be when using ice water for pour-over coffee.

Ice Water Pour-Over

Ice water pour-over, as the name suggests, is brewing coffee with ice water! Coffee grounds extract very slowly at low water temperatures. For example, cold brew requires at least 12 hours in the refrigerator, while ice drip extraction takes 6-8 hours.

Since pour-over brewing typically takes only a few minutes, when making pour-over coffee with ice water, FrontStreet Coffee chooses to adjust the grind size to BG 6M (72% pass rate through China standard #20 sieve) and uses hot water during the bloom phase, extending the bloom time to increase coffee ground extraction.

So the question arises: how long should the bloom be for optimal results?

Bean Information

Today, FrontStreet Coffee selected the Kenya Othaya FCS Chinga Factory Natural coffee bean. The natural processing brings rich, complex fruity acidity to this bean. When brewed using Japanese iced pour-over, it offers a very refreshing sensation. I wonder how it would taste with ice water pour-over?

Kenya Othaya FCS Chinga Factory Natural
Kenya Othaya FCS
Region: Nyeri, Kenya
Processing: Natural
Altitude: 1700-1950 meters
Varieties: SL28, SL34
Grade: AA

Experiment in Progress

Since FrontStreet Coffee only wanted to compare the effect of bloom duration on flavor this time, other parameters remained unchanged. Due to the changed bloom time, the extraction duration was also extended accordingly. To minimize errors, no additional agitation was added except for water flow stirring during extraction.

Parameters & Technique: 15g coffee dose; water temperature: 90°C hot water, 0°C ice water; grind size: BG 6M (72% pass rate through China standard #20 sieve); coffee-to-water ratio: 1:15

Bloom with twice the coffee weight in 90°C hot water. After blooming, add ice water at 0°C to 122g for segmentation. Continue pouring to 227g when the water level is about to expose the coffee bed. Remove the filter cone when the water level is about to expose the coffee bed again.

[One Minute Bloom]

Timing started at bloom, total extraction time: 3'35".

Flavor notes: cherry tomato and lime acidity, with honey and cream sweetness. Overall quite sweet and acidic, but with a slight under-extracted astringency.

[One Minute Thirty Seconds Bloom]

Timing started at bloom, total extraction time: 4'05".

Flavor notes: dried plum acidity, with mango and lemongrass flavors. The aftertaste has creamy and floral notes.

Comparing these two batches, FrontStreet Coffee found that the [one minute bloom] version, while having sweet and acidic notes, had slight astringency and somewhat thin flavors when tasted; whereas the [one minute thirty seconds bloom] version had more pronounced sweetness and a pleasant aftertaste.

Conclusion

When we extend the bloom time, it increases the extraction of coffee grounds to a certain extent.

If you want to try ice water pour-over, FrontStreet Coffee suggests you can improve coffee ground extraction by extending the bloom time or adding agitation during extraction.

Regarding making ice water pour-over, FrontStreet Coffee has several recommendations:

1. Due to the low extraction rate of ice water, you can adjust the grind size finer to increase coffee ground extraction. Since the grounds become finer, the water flow rate in the filter cone will naturally slow down, so you can increase water flow agitation during brewing;
2. It's best to prepare two pour-over kettles because we need hot water for blooming and ice water for brewing;
3. During the bloom phase, use hot water for blooming and degassing. The water temperature and amount can be slightly higher and more than normal pour-over. The bloom time can be extended until all hot water has drained. During degassing, you can also use external agitation to ensure all coffee grounds are thoroughly degassed.

That's all for FrontStreet Coffee's small exploration of ice water pour-over today! Everyone should give it a try!

END

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473