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Category: Coffee Filters

Posted on August 4, 2019September 2, 2019

An In-Depth Analysis of Coffee Filters

In this longer than usual post, I do a very detailed microscope analysis of various V60, chemex and siphon paper and cloth filters.

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I just publicly released my blog post on all the variables that affect coffee brew time (link in bio) ! In it you will find an in-depth discussion of why brew time is such a poor tool to communicate recipes or grind size, and how it's only a useful diagnostic if you are extremely diligent in keeping all the variables fixed in your brewing. I also just made my next blog post available on Patreon (link also in bio): it's a discussion of the mechanisms that cause astringency in coffee, and what astringency feels like. I also discuss ideas for measuring astringency, and how we might want to learn a few tricks from the beer and wine sectors for reducing astringency in our brews. 
#coffeescience #coffeegeeks #coffeebrewing #v60 #coffee #pourover #coffeeadastra
I just released my latest blog post (link in bio) in which I discuss flow uniformity in coffee brewing, based on computer simulations of percolation from the scientific literature ! It really helped me understand why small changes in grind size can sometimes result in more astringency even when no obvious or catastrophic channeling seemed to have happened. I suspect these simulations explain why; the percolation flow is naturally much less uniform in space at very small flow rates. I also think it's an important reason why all of my Buchner funnel brews to date have been quite astringent (my pump is very weak). Flow through the coffee bed is starting to look like a very important variable when we brew ! My following blog post is also available on Patreon (link in bio): in it, I discuss in great detail why I think total brew time is one of the least useful and communicable quantities for pour over ! And not only it’s already on Patreon, it’s also now available to @baristahustle Unlimited subscribers ! #coffegeeks #coffee #coffeescience #buchnerfunnel #v60 #coffeephysics
I just published a new method to make coffee concentration measurements precise to 0.01% TDS with a refractometer ! It features convenient steps to take so that you completely remove the issues of evaporation and temperature differences that could easily introduce errors of > 0.05% TDS in your measurements ! You can find out more about this protocol on my blog (link in bio). I also just made my next blog post immediately available to my Patreon followers (link is also in my bio): in that upcoming blog post, I talk about a scientific paper that carried computer simulations of percolation (last image) and I discuss the different variables that I now think affect extraction uniformity. It's not just about channels ! #coffeescience #coffeegeeks #coffeeadastra #coffee #refractometer #specialtycoffee #coffeeexperiment #coffeebrewing
This morning I’m treating myself with @gardellicoffees’ amazing Gesha Village Auction Lot 6. This natural Gesha is so floral it almost feels like drinking perfume (or at least what you’d think drinking perfume feels like haha). It has a nice and complex acidity that reminds me of pineapple and kiwi, but also of peach and lime. The taste ends with a nice, balanced sweetness that almost feels like bubble gum. I brewed this cup with my usual recipe (described on my blog; see link in bio) with Rao/Perger brew water, a 22g dose and 1:17 ratio, which got me a 323g beverage at 1.45% TDS for an avergae extraction yield of 21.3%. This is suprisingly high for a natural processed Gesha. I made some minor tweaks to my V60 recipe recently based on my turbidity measurements; I now pour a bit lower (14 cm above the slurry) with a 3-6 g/s kettle flow, and I prepare the nest shape with my finger rather than a chopstick (see photo). These modifications gave me a marginal ~0.3-0.4% increase in extraction yield but made my brews less astringent and cloudy. #coffeeadastra #coffeegeeks #coffee #pourover #GSC #GardelliSC
This morning I’m drinking a fantastic coffee roasted by @passengercoffee, the Alexis Gonzales washed Colombia varietal, from Colombia ! The tasting notes are incredibly accurate for me; it really has a bright black currant acidity with an intense and lingering sweetness that reminds me of pineapple and litchi. I brewed this one with my usual V60 recipe (see link in bio) with Rao/Perger water, a 22g dose, 1:17 ratio, 45 sec bloom with the EG-1 grinder at 7.0@700 RPM (burrs touch at 1.6) and obtained a 3:17 brew time, 1.46% TDS concentration and 320g beverage, corresponding to an average extraction yield or 21.3%. That photo is featuring @umeshiso_’s beautiful cupping spoon, thanks again ! I use it for stirring my coffee when I’m not cupping, just because it’s nice. #pourover #coffeeadastra #coffee #coffeegeeks #v60
For those of you who understand French, @cafe.normal just released their latest episode where I discuss various topics with Seb for more than an hour, including extraction dynamics, brew water, coffee grinders and more ! See the link in my bio for the episode. I really loved this discussion, and frankly all other episodes of the podcast too ! So much so that I binge-listened to the whole series in two days 😂 Thanks again to both Seb and Elise from @cafe.normal for the opportunity, I loved being a part of this awesome project. #coffeegeeks #podcast #coffeepodcast #coffeegrinder #coffeegrinds #coffeescience #waterforcoffee #coffeeextraction
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Website logo by Daniel Demay

All the better-looking photos on this website are by Noé Aubin-Cadot

Most Amazon links on this website are "affiliate", which means I get a small commission if you buy through them, at no cost to you.

Resources

  • Grind Size Application
  • Current V60 Recipe
  • A V60 Pour Over Video
  • Current Siphon Recipe
  • Flavor Wheels
  • Brew Water Crafter Tool
  • Water Recipes Spreadsheet
  • Bottled Water Spreadsheet
  • Coffee Filters Analysis
  • Cupping Statistics Widget
  • Extraction yield equations
  • Coffee control chart (percolation)
  • Coffee control chart (immersion)
  • Coffee Glossary by Mitch Hale
  • Specialty Coffee Association Standards
  • Barista Hustle
  • Scott Rao’s Blog
  • Mitch Hale’s blog
  • RSS - Posts

Enter your email address to follow this blog and receive notifications of new posts by email.

Join 229 other followers

Blog Stats

  • 123,459 hits

Category Cloud

Announcements Blind Tasting Brew Methods Brew Temperature Coffee Filters Coffee Grinders Coffee Processing Coffee Varietals Collaborative Posts Cupping Data Analysis Espresso Experiments Extraction Maths Particle Size Distribution Perception of Taste Physics Recipes Siphon Brews Storage and Maintenance Tasting Notes Tools V60 Brews Water for Coffee
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