Even more on iced coffee

June 7th, 2012

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….

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