Even more on iced coffee

So everyone is talking about iced coffee and I had a couple of quick thoughts that I want to share:

– First, I haven’t tried the hot bloom method Lorenzo Perkins wrote about in barista magazine
– I really don’t like room temperature toddy style cold brews.
– I had some tasty cold brew in Dwelltime in Cambridge, MA. I also had the weirdest, craziest and most unique cold brew ever at Barismo later that same day.
– I generally like brewing hot onto ice but I have a small issue with how we’re doing it:

I don’t think the 50/50 split works very well. I will offer a few reasons why, aside from the fact that I think we went there because it is conceptually easy to understand and explain and it is quite neat.

Problem 1: We don’t have enough solvent.

I think it is very difficult to extract correctly using half the amount of water we typically do. Especially with lighter roasts that don’t really want to give up the goodness. We can grind finer but we tend to get to a point where the water isn’t interested in passing through the coffee without additional pressure. So we’re pretty likely to underextract the coffee.

Problem 2: The maths doesn’t work for me.

So let’s say we’re aiming for a litre of coffee (so to speak) so we have 60g of coffee, and we have 500g of hot water and 500g of ice. So far so good. Here’s the problem – the 60g of coffee is going to absord about 120g of water, leaving us only 380g of liquid. (Approx 24% of our brew water never makes it down below).
Typically brewing a litre only 12% of our brew liquid would get stuck up there. We then dilute our 340g with 500g of ice. The resulting brew is typically quite thin/weak/tea-like if we’re being polite.

This obviously assumes all the ice melts, though we often tend to serve this with a little additional ice too.

Why not brew with a little more water, and use a little less ice? I’d encourage people to try a 60/40 or 75/25 split and to see how it goes. The ice should still perform its ultimate function – making the coffee cold and refreshing – but hopefully we end up with a more balanced, fuller and more satisfying brew.

I’m probably making some mistakes here, because I’m super tired after attending Camp Pull-a-shot which I will try to write about soon. Feel free to harass me on twitter, though I’m about to jump on a plane. Expect a possible retraction….

24 Comments

  1. we usually do ours on a fetco 2031e with the following variables:
    1.89l batch size (1/2 gallon) with 1.89 kg of ice in the decanter
    8:30 brew time
    12% prewet
    1:00  prewet delay
    :30 drip finish
    200° water temp

    the reason i use those variables is i pondered the same problem you did – how do i get the proper extraction while using half the water and 1 bar of pressure? so i doubled the brew time. i’ve had good results and while i’ve not run it through a TDS test, it seems to be strong enough. i also don’t notice any bitter flavors from the brew time – the result is clean, sweet, with the body i want from an iced coffee.

    that said, i tried your suggestion this morning and did a batch with a 60/40 split (so 2.27l batch size and 1.5kg ice). the coffee didn’t quite cool down to 32°, and the top layer in the decanter was slightly warm. it chilled after stirring it but i think the 60/40 split is insufficient to cool it properly. the result was far brighter than our previous brews (the coffee is mtnairroasting.com’s Finca La Bisunga / Costa Rica). think sour mix while the previous brews were more good quality orange juice.

    i’m going to do another batch with a 50/50 split and A/B them, will report back.

  2. From what you’ve told me about your writing, I can only imagine how tired you are from the travel!

    First off (and I think this might be something that Wendelboe is cluing on), I wonder if we need to worry so much about everyone adhering to any particular standard?  The NYT article suggests that one method of brewing is necessarily better than the other – and we seem to have that attitude within the 3W coffee scene.

    I think your experience in Boston is more along the lines of what interests me about coffee, barista craft and individual shops.  The fact that you experienced two distinct coffee experiences on one day is something that should be lauded and celebrated because maybe it’s an indication that we’re stepping out of these prescribed comfort zones and the baristas leading the shops are moving to their own vision.

    As someone who”s worked in fine dining, I’m sure you can appreciate that the food and experience at TFD is not the same as Noma!

    I definitely agree with you on the ratio thing.  At Spro, we’ve been working with updated parameters of 260 grams of coffee to 4300ml of water and ice.  But what’s really been on my mind is how to properly and consistently regulate the water flow to the coffee, and we’re starting to experiment with certain pumps that can deliver a constant rate of water to help improve cup quality.

  3. after going from the 60/40 to the 50/50, i felt like the 50/50 was (as james mentioned) too tea-like and possibly underextracted. i’m going to see if i can find a workable solution to making it 60/40… thanks for the help james!

  4. I made my first iced coffee a year ago. After a few tries, it still felt too weak and watery. I decided to brew some coffee, and turn it into coffee ice cubes. I was VERY happy with the resulting iced coffee. I roast my own coffee beans, and did not find any strong preferences for which coffee to turn into ice cubes.

  5. We find 60:40 or even 66:33 to get the right balance of extraction (strength) and final temperature. A few other points:
    – Ice can be ANY temperature below 0ºC – ice from a deep freezer will have much more cooling power! Using VERY cold ice could allow you to brew at 75:25 and still achieve the right temperature.
    – Crushing the ice (or using smaller blocks) will cool it faster.
    – Chilling the receptacle also helps – just like heating the receptacle for normal pourover.

    Lastly, we in the Southern Hemisphere are freezing and jealous of your iced coffee drinking weather!

  6. Yes, I’d like to re-emphasize what Stu says above:

    There is a big variation with ice temperature: ice from a freezer is usually 0F (-18C), normal bar ice is much warmer.  The temperature of the serving vessel, whether it is insulated, the distance and thickness of the drop, the ice size, etc. all make a difference as to the cooling speed and ultimate dilution.  The Japanese method (flash cooling, ice brewed, etc) is a technique, not a recipe, and must be adapted to various conditions.  In my experience, using the minimum amount of ice to achieve a cool finished coffee (say 45F/7C) usually winds up creating the best flavor, but the percentage of ice it takes to reach that goal varies from 20 to 50 percent.

    Peter G

  7. I like Jay’s point that there cannot be ONE way to brew coffee, either iced or hot, and anyone who tries to convince me otherwise is naive at best. Coffee, and our enjoyment of such, is totally subjective. I don’t like cold brewed coffee, I prefer my Clever iced coffee method (https://vimeo.com/26302905), and didn’t drink it until I came up with this method. However, I have had great iced coffee in both cold brewed and “ice-brewed” methods. As long as we’re taking care of the coffee, and we’re presenting it in it’s intended form, let people like what they like. There should be no “iced coffee war.” 

  8. I usually find that  a 65/35 hot to ice split works really well for just about any coffee, i’ve tried a lot of ratios before hand but i like to find a ratio for everything thats practical and won’t ever fail me.  I agree with Peter I don’t think Japanese style iced coffee needs to be freezing cold when done brewing just cold enough not to melt the ice when adding it, I’ve seen a lot of people making coffee this way resulting in an over diluted cup. My big problem with a lot of shops is that they don’t take into account how their coffee tastes in 5 minutes! I mean really, some it taste like dirty water. 

    The hot bloom methods works really well the only problem I’ve had is that it can make toddy taste a bit astringent if the bloom or the brew is prolonged, I’ve been doing hot bloomed toddy for 2 years now. I’ve found that using a 10% of total water volume to bloom using the dispersion screen and waiting until its fully degassed then adding the rest of the water (i used iced water)

    I was talking to Mr. Perkins and he mentioned that the Yama Cold drip was meant to make coffee in 3 hours and thats something i really want to experiment with, though i haven’t had consistently good coffee out of them…

    call me crazy but the best coffee i’ve had has been from my wife brewing a Kenyan and fooling me into thinking she had made japanese style iced coffee… when it was a chemex she had made in the morning and she had put it in the fridge. It tasted like guava and passion fruit punch with the tartness i look for in iced coffee like a freshly made LIMEade.

  9. This issue has long been on the minds of the world’s martini makers. Although people like to make all kinds of outlandish claims about the ‘purity’ (read: no dilution) of their martinis, dilution is a really important part of the drink. I’ve always used a non-melting obkect to do the cooling (stones, ballbearings pink elephants etc. that have been frozen) and then replaced the melt with a controlled amount of water from a known source (ice is usually made from pretty ropey water).

  10. Anyone ever try a jockey box type non melting quick cool?   I am going to try a funnel ice-water and coil?

  11. Did I ready 8:30 brew-time correctly?

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  13. There are shops in NYC that use similar methods but how would you do it then? Are you sugesting to flash cool the coffee??

  14. Brian, I have totally tried this A few years ago… I made a contraption that held a beehouse dripper on top of a funnel that connected to a spiraled copper coil which was submerged in a salted ice water bath. the coil exited at the bottom of the ice bath into a waiting carafe. when I brewed the coffee in the dripper, it ran directly from the holes in the bottom into the funnel and down the copper coil into the “heat exchanger” and then exited into the carafe. the temperature of the liquid was 75F.

    Tasted great, but I had a problem witth the repeatability/practicality of the set-up. my first impulse was to buy a “water cooler” not unlike you would find in an office where one would place a 5gal bottle of drinking water dispenser and, when turning a tap, receive instantly chilled water. this seemed great, but I think the biggest challenge would be taking a system designed for cooling water from 70F to 40F (a 30degree drop), and attempting to accomplish a 130F drop (200F to 70F). cleaning also seemed to be a big hurdle as well.

    a more ideal situation might be to take brewed coffee and instantly spray it against a series of plates or screens. this would also aerate the coffee as well as cool it.

    more things to dream about…

  15. yeah. it’s not really 8:30 contact time, just long gaps between pulses on the fetco so water can get through the large amount of grounds. i’ve not noticed any drawbacks.

  16. One slight detail I think we cannot neglect(and I’m sure most of us have thought of this) is the importance of the amount of ice we use. When the hot brew hits the ice it melts and therefore begins the balance out the “concentrate” of coffee. If to much ice is in the decanter than proper balance does not take place. This is just a little issue I have noticed in my cold brew journey. 

  17. I’ve been experimenting with doing iced coffee pour overs using the glass handle Chemex and the Kone v2.  I have been using a ratio of 5/8’s water and 3/8’s ice and it seems to be working well. 

    I always cool the Chemex, but I have found that if you cool the top wall of the Chemex (where the kone sits against) I have had a significantly lower extraction. Visually the bloom is smaller, and the cup presents a sharper more low quality acidity. Have you experienced this happening?

    I have also found that adding ice to the finished product to cool it further has drawn out a more tannic style acidity, which is very biting in the back palate.

    Thoughts?

  18. I really enjoy the Hario Fretta to brew my iced coffee in. The unique design allows the coffee to be chilled as quickly as possible during the entire brewing process. I’ve tried so many methods and this is the one I think produces the sweetest most balanced cups and is also very repeatable.

    30g Coffee
    200g Ice (I prefer large ice cups from a tray)
    310 Water
    A finer grind setting than you would normally use for a V60
    3min brew time (with a 60g 30 sec bloom)
    More than normal amount of agitation during the entire brewing process

    When done brewing I add any left over ice that did not melt during the brewing process and stir with a bar spoon. This brings the coffee down to a perfect serving temp and if you pour it over ice again it will not immediately.

    I agree with Jason Dominy that there is no one way to brew coffee hot or iced. I really enjoy iced coffee made with a fetco. The Yama cold brew towers produces some really interesting results when using a hot bloom tech. I have done the hot bloom toddy and still have not tasted a cold brew with a toddy that I really enjoyed although I know many customers that love it with a little milk in it.

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