Updated: Feb 14
Brewing coffee can be a bit of a science experiment in the art of extracting all the delicious flavor compounds locked inside the roasted beans. Factors like surface area, water, heat, brew ratio, agitation, and time need to be set appropriately with your chosen brewing device to get that delicious cup. Most of these factors have guidelines, rather than hard set numbers, to get you in the ballpark as each coffee will be a little different in how it brews. Ultimately your taste buds are the determinant to what you prefer. This article outlines the big factors and guidelines with simple adjustments so you can get your brew method and coffee “dialed-in” to your taste preference.
Understanding Brewing Factors – Build from a good foundation
Water – Clean, odorless, neutral pH with proper mineral content.
Its 98% of your cup and the foundation of a good brew. Attributes like pH and mineral content will determine what and how much is extracted from your ground coffee and directly influences the taste in your cup. As a general guideline, if it doesn’t taste good to drink it won’t taste good to brew with. At a minimum make sure your using filtered water. For better results consider using Third Wave Water packets, mixed with distilled or reverse osmosis water, an extremely easy way to get great brewing water and help protect your equipment. Quality bottled water options are great while traveling or at home.
Heat - 195°-205°F
Too little heat and you’ll under extract, too much heat and the coffee will over extract. Most brewing methods call for a water temp between 195°-205°F to properly extract. Dark roasted coffee extracts more easily so brewing a little cooler may produce a better cup. Brewing a denser or light-roasted coffee may require hotter water to better unlock its flavors. If you’re using a kettle without a thermometer, about 30 seconds off a boil will put you in this temperature range. If using an automated machine, check to see if it is putting out hot enough water.
Grind Size – Surface area relates to extraction. Match to brew method.
Grinding your coffee beans breaks them apart and exposes more surface area to contact with the brewing water. The greater the surface area, the greater the extraction. How coarse or fine your coffee is ground should be matched to your brewing method. Grind size is a good way to control flavor, whereas your coffee-to-water ratio controls strength. Grind a little finer to extract more flavor, coarser if it needs to be toned down a bit.
* Aeropress has many recipes and attachments. Grind size can vary with attachments and different recipes.
Coffee to Water Ratio – 1:15 to 1:17
This ratio is your strength control. If the flavor tastes good but its too watered down or overpowering, adjust your coffee-to-water ratio to bring it into balance. The Specialty Coffee Association standard is 60 grams of coffee per 1 liter/33.8 oz/~4 cups of water. This equates to a 1:16 ratio. Start with that and then adjust the ratio to suit the coffee you are brewing and your taste preferences. Brewing with a scale will give you the most accurate results. Without one, just remember:
1 tablespoon of coffee = 5 grams
1 ounce of water = 30 grams
Below is a quick reference table for a 1:16 ratio:
*Cup size can be a point of confusion. The standard international measurement of a coffee cup is 4 oz. But the average coffee mug is 8-10 oz. Which is why your coffee pot markings never match with what you are drinking. Chart above uses a cup as 8 oz since that is closer to actual use and works better with manual brew methods like a pour over or french press.
Time – Set to brew method and use to measure other factors
Simply how long the water and coffee grounds remain in contact with each other. Longer contact time means more extraction. Flavor extraction happens on a timeline, starting with enzymatic and fruit flavors first, followed by chocolate and caramelized flavors, and finally carbonic roast flavors.
Time, grind size and brew method are all closely tied together. In a French Press the coarse coffee and water will steep together for about 4 minutes before being poured. An espresso shot, with its fine grind, pulls in about 30 seconds. Drip coffee, with its medium grind, and water only being in contact as it passes through the grounds in the filter takes around 3 minutes. Grind size in drip/pour over methods will speed up or slow down the flow rate through the bed of coffee; finer grinds slowing the flow rate down and increasing extraction and coarser grinds allowing the water to flow quickly and extract less.
Time can also be tweaked based on what coffee you are brewing. Brewing something like an African coffee that is lighter roasted and has bright, fruity, acidic flavor notes, you may way to brew a little quicker to highlight these notes. Brewing a darker Indonesian with earthy and roasted notes, you may want to extend the brew time slightly to highlight these. Experiment different brew times with the same coffee to see how the flavor changes.
Agitation – Minimize for consistency
Greater agitation equals greater extraction. If you have repeatedly dunked a steeping tea bag you’ve seen this in action. Agitation during coffee brewing commonly comes from pouring the water, or when the grounds are stirred. Agitation (or lack thereof) is determined by brew method and the recipe you use with it. Agitation is hard to repeat consistently so most methods will try to keep this minimized. If recipe calls for stirring, use a set number of stirs for consistency. Gooseneck kettles or a thermos that control the water flow are great for pour overs. Automatic machines will control this for you.
Properly controlling these factors for your chosen brew method will make sure your coffee is neither under-extracted nor over-extracted and unlocked all the delicious flavors and aromas. Start with the general guidelines for your brewing device and then use your taste buds to tweak. Have fun experimenting too; brew something way outside the guidelines to see what a really under or over extracted cup tastes like, it will help you hone your taste buds and make a great cup.
How to make adjustments
My Coffee Tastes….
Problem: Coffee is under-extracted
Solution: Grind finer and increase the brew time. Greater surface area will increase extraction and finer grinder will slow down flow rate in drip brewing methods. Also, make sure your brew water is hot enough.
Bitter, astringent (drying feeling on the tongue), papery
Problem: Coffee is over-extracted.
Solution: Coarsen your grind and reduce brew time. Coarser grind will decrease extraction and speed up flow rate through drip brewers. Also, make sure you brew water isn’t too hot.
*If you’re using very dark, oily, burnt, over-roasted beans, then bitter and ashy will likely be the only flavor profile they will produce.
Too Weak or Too Strong
Rules can always be broken so if you like an especially strong cup of feel free to experiment beyond the 1:15 end of the spectrum.
Nothing like the cup from the café
Problem: Brewing water (assuming other adjustments have already been tried)
Solution: Filtered or bottled water or make your own perfect home coffee brewing water with distilled water mixed with Third Wave Water packets. Using tap water is probably the biggest difference between the café and achieving great results at home.
Hollow, empty, lacking in taste
Problem: Coffee is probably stale
Solution: Check the roast date on the bag and buy fresh in quantities you expect to use before it will stale. Coffee’s peak flavor is typically between 2 and 14 days after roasting. Most coffees will hold good flavor out to 30 days after roast but will typically stale quickly after that. Buying from a specialty roaster and avoiding the supermarket will help ensure you are getting fresh, skillfully roasted beans.
Questions about your brewing and how to dial in to your taste? We would be more than happy to help you perfect your brew. Contact us and let us help you dial in your brew.
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