Go to the Article: Getting the Good Stuff
Very interesting discussion on the 20% ideal extraction.
Push past 20% with the right coffee. A high-quality, light roasted bean with higher sugar levels will taste good—sweeter with a clearer profile and cleaner acidity—with an even extraction toward 22-25%. ChefSteps members might already own test sieves; these allow you to create a narrow distributions of grounds without a high-end grinder. With a narrower distribution of particle size, more even will be the extraction, and better will it taste to increase extraction of the material.
I've had great brews up to 26-27% on rare occasions, but often it is very much about both grinder used and roast development - lighter roasts can often be poorly developed and you'll struggle to extract much even with a super even grind.
I have noticed a need to change the grind size with the age of the bean. I buy beans the day after roasting. During the 2-3 weeks I use the bean I may change the grind size up or down. I have not followed this closely so I do not have any specific data to share. Just wondering if level of extraction possible is affected by age of bean. What say the crowd?
Right, thoughtful and careful roast development must be critical to a full extraction; I suppose it can be a persnickety poise during roasting to dance about that fulcrum of perfection: not too little, not too much. (But I've never myself attempted to roast!) What sorts of coffee have you brewed flavoursomely to 26-27%? Any that fall around 25%—which I've tasted and enjoyed personally—have been especially tart and sweet Kenyans.
When you change the ratio of coffee to water, doesn't that also affect extraction? Let's say I started off with a 7.5% ratio (75 g coffee in 1000 mL water) and found that perfect grind setting which is one step coarser than producing a cup that is too bitter. Fine. Now let's say I find this coffee to be too strong, so I change to a 6.0% ratio. This means that for every gram of ground coffee, there will be more water available to extract 'good stuff' from it, increasing my extraction. The strength of my coffee is perfect, but wouldn't it now taste bitter?
It seems the grind is what gives you the extraction (surface area exposure). If the coarse is right you are going to get 20% of extracted coffee no matter the amount of coffee. More or less coffee ratio just means how much 20% extracted coffee you want in water.
What are your thoughts on the SCAA standards in terms of the cupping ratio? Theirs works out to 0.055g for every ml of water.
Will a Brix refractometer work or is it specifically a coffee refractometer....? I would love to try the experiment with old and fresh roasted beans brewed to the same variables and extraction to go head to head and vanquish the "old coffee is fine"
(well old coffee does work great sousvide with butter for spinach and steak...)
I'm getting some peculiar results with the French press method. In the past of done it the old fashioned way: very course grind (36 on my burr grinder), brew for 4 minutes, stirring a couple of times, and plunge. This gives coffee with a full body and rich flavor, but is a bit light on acidic notes.
I've now tried a finer grind (20) and used the chefsteps method: 4 minutes without stirring, one stir, and then a three minute rest before pouring through the filter. The results were a crisper acidity, but less body. The finish was metallic and really too acidic.
So I tried an even finer grind (14). This still gave a thin body, was still a bit too acidic, AND was too bitter. Not sure where to go from here.
I may abandon the chefsteps method, but try the traditional method with a finer grind. Thoughts?
(This is with very good quality Stumptown coffee, roasted a couple of days ago).
You'll want to check the VST Coffee Tools app available for iOS, Android, Windows and Mac. Works with or without a refractometer and allows you to store your results notes for helping with empirical process.
