Cold Brew

Here are some questions we were asked by Esquire recently concerning some research they were conducting into trends in coffee. As it is summer we thought you might like to hear about our thoughts on cold brew.

Firstly, do you know how long cold brew has been in the UK?

Cold brew methods emerged in the UK around the summer of 2010 and where informed by the uniquely independent Japanese coffee culture. Much of the brewing equipment that wasn't homemade was developed in Japan harnessing its beautiful glass blowing traditions.

How exactly does the cold brew process work?

There are two categories of cold brewing; drip and immersion. The drip method quite literally calls for cold water to be added drip by drip through a precise flow restrictor into a bed of ground coffee that is suspended above a filter. Gravity fed liquid coffee then collects in a jug underneath. The drips need to be dispersed evenly across the surface.With our Hario (TM) brewer, drips are landed onto a steel pin that cascade in smaller droplets across a paper filter that is laid over the coffee bed. This prevents the uneven erosion of grinds.Prufrock's method calls for a two second interval between drips over a period of approximately four hours.Try collecting the brew in sections (say every half hour) and liquid blending separate parts of the extraction to optimise the taste and strength. We brew with the target ration of 65g/L but entry level brewing equipment won't give pinpoint control of the drips per minute rate. Liquid blending allows us to zone in on optimum extraction rather than just sticking to a set brew ratio.An easy immersion method is the Toddy (TM) performed with a very fine-mesh nylon sack full of coarse (cupping) ground coffee steeped to taste in cold water for several hours. Use a ratio of around 70/L. Drain all the liquid from the grinds once the desired taste is achieved. The toddy much like an home brewing keg has a tap at the bottom for draining. For greater clarity, fine sediment can be filtered out after brewing is complete with a paper or nylon filter. Better still, fine particles can be sieved out using a 1/4mm screen prior to brewing. Store in the fridge for not longer than two days.

How does it change the taste of the coffee?

Expect much less aroma and muted acidity but a syrupy port-like textural quality that makes a great substitute for Campari in a Negroni and mixes fantastically well with tonic. For best results choose brightly acidic and lightly roasted coffee and grind fresh.