What's the big deal about pour-over coffee?

Question

For the last ten years or so, I think, pour-over coffee has been very trendy (and, usually, expensive). You often see these filter racks in coffee shops:

As far as I can tell this is identical to the coffee brewing method I grew up with: the plastic Melitta cone.

We were not really fancy coffee people. The cones were quick and easy (and storable in a cupboard, unlike a coffee machine). The coffee was tasty. For that matter, I still use a Melitta cone when I go camping. So my question is: why did pour-over coffee become such a big deal? Is it just that the barista is making you a bespoke cup from scratch instead of pouring it from the urn? Or has there been some advancement in the state of the art in the last thirty years?

Answer 1

Pour over systems give you the ability to control the water flow through the coffee grounds with a high level of precision whereas a drip brewer does not.

I will admit, this is a bit of a trend, but there are very real differences in the taste of a pour over versus a drip brewed cup of coffee.

• Blooming -- Gets rid of trapped Co2. Easy to do in a pour over, whereas in a drip brewer, I don't believe the grounds are allowed to bloom. If you don't let the Co2 offgas, you get metallic flavors in the cup. Typically not really a problem since the majority of the gas is gone inside 12-24 hours anyways, but pour over allows you to completely optimize this.
• Cleanliness of cup -- pour overs are known for producing a very clean cup of coffee, that allows you to highlight the top notes in a coffee like florals or fruit flavors. This is the polar opposite from French Press, and drip brewers either use paper filters that aren't pre-soaked so may relay a papery flavor to the coffee, or use a metal filter which will allow quite a bit more coffee oil through the filter and thus muddy the cup (slightly).
• Grounds saturation -- Typically drip brewers don't have a very good spray head in the drip brewer, so many times you can get a filter of grounds where the center is indented after brewing and the outer grounds may not even be wet in some cases. Obviously, grounds not wet is a bad thing. The indentation is also a bad thing. It basically means that more water is being passed through the center of the filter than elsewhere which means you don't get even extraction.
• Timing -- You don't want to pass water through the grounds too fast, nor too slow. The reasoning for this is variable solubility rates of different compounds in the coffee. Case in point, if you grind really coarse and 'brew' your coffee in 1 minute, what's going to happen is the citric and malic acids in the coffee grounds will extract very easily and the other more complex flavor compounds will stay in the ground. This is going to produce a sour cup of coffee. Pour over allows you to make minute adjustments to ground saturation timing that can produce some wild flavors in a cup of coffee.

All this being said.. I still use a drip brewer for my morning cup of coffee because I'm usually running out the front door trying to get to work. Does my drip brewer produce a good cup of coffee? Absolutely. Can I get a better cup of coffee with a pour over? Probably. It's simply a quality / time trade off.

Answer 2

Nate sums up the technical aspects nicely in his answer (+1!), so I'll just add a few other aspects.

You also asked for the difference between the pour-over today and back then and where the difference to getting a cup from the big batch urn was.

As far as the big urn goes, it is a question of timing. At the "single serve pour-over" coffee shop your cup will be brewed right before you get it. The longer brewed coffee stands, the more chemical reactions can happen that can produce unwanted flavours. If kept warm in a thermos container, this effect is even more noticeable.

Along the same lines, the time between grinding the beans and brewing them plays a role in keeping as many of the desired aromatic compounds in your drink - widely discussed on the net and also on the site. I strongly assume that a coffee shop with the pour-over setup from your question would also grind the beans for every serving.

Which leads to the very interesting conclusion that (from the point of view of a coffee aficionado) the pour-over of our Grannies, who hand-cranked their coffee mill every morning and brewed by hand is actually pretty similar to the latest trend of pour-over coffee bars. The latter might be putting more effort than ever into selecting the "best" beans and roast, measuring water temperature and extraction times, but compared to dumping pre-ground coffee (aka coffee-flavored sawdust) in a huge machine and keeping the sludge warm for hours, the old and the retro method are pretty much the same.

The big deal of the new pour-over trend is probably that many consumers have come to appreciate the finer aspects of coffee - not unlike wine aficionados.