I'm an advocate of Scott Rao's books and work. In particular I have previously conducted some experiments in relation to his views on the 'high and dry' phenomenon that seems to be common in baristas' pourover technique. As a result I've universally avoided ending up with any form of V-shaped cone at the end of my pourovers, aiming instead for the convex dome shape of grinds in the filter cone, that results from spinning the slurry during extraction and drawdown.
I was wrong.
But that isn't to say I don't still firmly support Scott Rao's assertions. I believe I just misinterpreted them.
Ongoing experiments have shown how vastly different the extraction of two different coffees can be, despite using exactly the same parameters and technique. Obviously grind always needs to be adjusted to the current state of the bean, but grind alone is not the best way to achieve your target pourover results. Pouring technique must also be adjusted.
Sometimes there is no way to achieve a dome of grinds at the end of a pourover without resulting in over-extraction. The stirring required to ensure that grinds are not left under-extracted at the rim of the V60 can cause too many solids to diffuse from the grinds, overshooting the target TDS.
For a week or so I've been trying to achieve a TDS of around 1.35% for a Tanzanian Kilimanjaro, but every time the reading came in at around 1.6% and the taste was too strong. In the end I have managed to find a way to hit my target within an acceptably long dwell-time, but it has meant grinding a fair bit coarser and also changing my pour when brewing these beans. The 'new and improved' pour is probably also better in terms of maintaining brew temperature. It involves a constant slow pour all throughout the brew, rather than many small pours. Infact at times it encroaches on a drip rather than pour.
With such a slow pour the grinds never have a chance to rise up the side of the V60. This means that at any point in time all of the grinds are being extracted evenly, and the 'high and dry' thing never happens. It also therefore means that there is no need to stir. The last 20g of water is just poured slightly quicker to ensure everything is covered, and then the drawdown is allowed to complete... the majority of which takes only perhaps 10 seconds, with residual dripping for a further 10 seconds.
The result is infact a small amount of concave coning of the grinds, but the majority of the slurry remains flat. I deem this acceptable since it has taken place over only the final 10 seconds of the brew, and also the slurry rim (the 'high' grounds) is just 1cm above the flat of the central slurry.
In the cup this works a treat. The TDS and Ext % are right, and also the taste is wonderfully balanced due to the grinds being evenly extracted throughout the filter.
Now I'm not saying this is how I'll be doing it every time. With a Mandheling I have at the moment a good stir with a chopstick at the appropriate time during the brewing process is absolutely the right thing to do, and helps me hit my target extraction. The point is, there is no single correct technique. It seem that the skill lies in having a repertoire of techniques to enable an appropriate response to the how the beans are extracting.
My learning continues. I reserve the right to compose another post in a few months, denouncing THIS post as complete bollocks!
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