Here are a few tips for our experts to improve the quality of your shots at home
1. Use ‘rested’ coffee: coffee that is left for a 2-3 week period after roasting and before espresso brewing has had enough time to off-gas and release some CO2 from within the bean. If you make espresso with coffee that is too fresh, under the 9 bar pressure that most espresso machines exert, the CO2 held in the coffee can be converted to carbonic acid. The acid imparts a harsh or astringent taste (think Coca Cola flavour).
Check the roast date of your coffee and open the bag once it is two to three weeks post roasting to mitigate any CO2 astringency.
2. Use an espresso scale: making use of an espresso scale that can fit on your machine’s drip tray is a game changer. This allows you to consistently measure the correct amount of coffee (dose) going into your portafilter, and it also allows you to measure the time and yield of your shot. Your dose should be defined by the capacity of your portafilter basket. Most home coffee machines recommend 18-20g so check your machine’s instruction pamphlet to see what dose is recommended.
3. Grind just before brewing: investing in a manual or automatic grinder will not only introduce gorgeous aromas to your kitchen, but also decrease the oxidisation of your coffee. Pre-ground coffee oxidises at a quicker rate than whole beans, losing its complexity far sooner.
4. Prep your portafilter: it is important to run some hot water through your portafilter to get it up to temperature, preventing any heat loss that would occur during the first shot.
When that is done, grab your portafilter out and with a microfiber towel or a tea towel, give it a good wipe to remove any moisture. Unwanted moisture in the portafilter can be detrimental to your shot resulting in a bitter, over-extracted taste.
5. Dialling in with a recipe or ratio to start: the ratio describes the DOSE:YIELD. A great place to start is a ratio of 1:2. That is 1 part dose (grams coffee in your portafilter) to 2 parts yield (gram of espresso you pull).
If you were using 18g of coffee in, you would be aiming for 36g of espresso out.
5. Take note of your shot times: To get your shot time, click the double shot button on your machine and start your timer in unison. When the machine finishes extracting your shot, hit the pause button on your timer, and you will have your extraction time. A good aim is between 24 and 30 seconds but the ideal extraction time is the time that produces the espresso shot that tastes the best.
6. Tinkering to taste: If your shot is tasting bitter or taking too long (well over 30 seconds), it is most likely over-extracted. Try grinding a bit coarser.
If your shot is tasting acidic or extracting too quickly (well under 24 seconds), it is most likely under-extracted. Try grinding a bit finer.
Happy Brewing from the Stash Team!