Penned by Swee Heng
I want to be upfront with you – I have not always been a fan of cold brews. I have dabbled in it before, chatted with friends in the coffee industry about it, and even exchanged recipes and pointers. But there’s a reason why Cold Brews never made it on the TCR Menu in the past – it just wasn’t great-tasting to me!
I was so ready to shelve Cold Brew in the dark basement of my consciousness. But as the COVID-19 storm came (which basically destroyed the entire dine-in/customer service side of the café business), when we decided to move into Bottling of Handcrafted Drinks, a part of me went “Maybe just one more try?”
Wait up…what exactly is Cold Brew?
For readers who don’t know what cold brew is: Cold Brew is made by immersing medium-coarse coffee in cold/room-temperature water, extracting coffee flavours over several hours. What I have described is the cold-steeping method, which is what the vast majority of cold brew producers use rather than the unscalable cold-drip method. Cold Brew is not to be confused with Iced Brew or Iced Filter, the latter is made by first hot-brewing followed by chilling the coffee.
Cold Brews have undoubtedly been placed on the pedestal, as proponents of this brewing method assert that the resultant coffee is less acidic. However, if you have been tasting many cold brews from different cafes, you might find that they all taste fairly similar.
And that has to do with the relatively low water temperature used for extraction – in the absence of high temperatures and therefore with lower thermal energy, a lower concentration of compounds are extracted from the coffee. If you proclaim that the coffee has “lost its character”, I would be leaning to agree with you.
And that was my main gripe with Cold Brews. Most of the cold brews I made tasted similar-ish. More importantly, they did not taste bright. Even an Ethiopia Yirgacheffe yielded a cold brew that was, in the opinion of my palate, dull.
So…what’s the surprising discovery?
I’m glad you asked! In my deep-dive in the literature surrounding Cold Brew, I chanced upon this interesting technique known as Hot Bloom. In short, we “bloom” the coffee using a small volume of hot water before adding cold water to reach our desired brew ratio.
We ran a really simple head-to-head blind taste test pitting the usual cold brewing method against the hot-bloom, cold-brew technique.
Side-by-side Taste Comparisons
The Infinity Blend – Cup B (Hot Bloom) tastes sweeter, fuller flavour, while retaining its body.
Ethiopia Haru Suke – Cup B (Hot bloom) has fuller acidity of Berries, sweeter
I was pleasantly surprised by the cold brews that have undergone hot blooms in both instances. For the medium-roast Infinity Blend, having a hot bloom actually increased the liveliness of the coffee and brought out fuller flavour. The light-roast Ethiopia Haru Suke tasted like sweet strawberries (finally a Cold Brew with the distinctive Ethiopia fruitiness!).
Making Sense of the Results
Hot Bloom makes use of the concept in pourover brewing – bloom the coffee by adding hot water (about 2-3 times the coffee’s mass) in order to release CO2 and prepare the coffee for more even extraction subsequently. By introducing a hot bloom in the first minute of brewing and subsequently adding cold water to bring down the overall temperature, water can do a better job of extraction.
This line from Cold Brew company Bruer sums it up best: “Essentially, the idea of using a hot bloom is to release easily dissolvable volatile compounds that produce the fruity and floral qualities to the brewed coffee that cold water alone may not extract entirely.” (Source)
If we use hot bloom, is it still a Cold Brew?
That is a very fair question. I would consider the Hot Bloom Cold Brew method a Hybrid technique, as it doesn’t extract purely using cold water as per the definition of Cold Brew. But the results are very apparent – I would proudly serve Cold Brews using the Hot Bloom method and bring out their origin characteristics.
And now, finally, Cold Brews are on the TCR menu 😊