Advanced Brew Tips
The higher the pour height, the more turbulence in the slurry.
When choking occurs, there is excessive turbulence or significant amount of fines migration; your pour height is too high or your grind setting is too fine.
We usually recommend:
Higher pour height for soft beans or larger dose(deep bed depth)
Lower pour height for hard beans or smaller dose
*how to tell the bean hardness: high grown beans tend to be harder and low grown beans tend to be softer.
The optimal pour rate depends on your pour height. Select your pour height, then adjust your pour rate just high enough to avoid letting droplets appear in the stream.
*Inappropriate stream with droplets: you can’t get the ground bed disturbed with this stream.
*Ideal vertical pouring without droplets in the stream.
Keep your pour height and pour rate stable
For even extraction, keep your pour height and pour rate as stable as possible.
Keep your stream vertical as possible
To maintain a vertical stream, move your kettle relatively slowly in a circular motion to leave your stream undisturbed.
Spin the slurry after each pulse
Do “the Rao spin” after each pulse to avoid channeling and uneven extraction. The spin break up the channels, in particular, laminar flow. Flat coffee ground bed after your brew is a good sign of even extraction.
*Flat coffee ground bed after drawdown.
Do NOT let the coffee bed appear(main pour)
When you pulse, resume pouring before the bed appears for consistent slurry temperature and better turbulences
*Time to resume pouring.
Drainage flow rate should be as consistent as possible
When the drainage flow is too fast in the former half of the brew, you are more likely to create channels. On the other hand, slow drainage flow in the latter half indicates that there is clogging/choking in your brew.
Rinse your filter with appropriate amount of boiling water
We recommend rinsing your filter and preheating your brewer beforehand with appropriate amount (200g-) of boiling water.
Grind fine enough that there are no boulders in your grounds
Boulders (especially coffee ground particles larger than 800microns) are one of the biggest causes of under extraction. Grind fine enough or sieve the grounds to make sure that there are no visible boulders in your grounds.
If you are using a refractometer, grind finer and finer until TDS and EY stop increasing on your recipe, then go back one notch. Basically, coarser grinding creates less amount of fines. Coarser grind setting is better unless it yields less TDS/EY.
*Flat ground bed without visible boulders.
Consider your beans hardness and size
Bean hardness affects your grinding and brewing quality especially when grinding with a hand grinder or home grade grinder. Hard beans can sometimes be ground as boulders, create more amount of fines or less efficiently extracted. Usually, smaller beans tend to be denser and harder than larger beans. If you are using a home grade grinder, we recommend picking some smaller beans before grinding.
Do NOT compress the dry grounds
If you compress the grounds, you’ll likely create clumps which can be a significant cause of under extraction and channeling. Do NOT level the grounds by your fingers or spoon, shake the brewer to make the bed flatten.
*exception: when you use cone brewer like V60, we recommend digging the ground bed and creating a swirl in the middle of the ground bed with your finger or plastic/metal stick.
RATIO and DOSE
We usually brew on a 1:17 ratio with a great commercial grinder and a Brewista Artisan kettle combination. We recommend a 1:16 ratio for home grade grinders.
To pre-wet the grounds evenly, we recommend a 1:3 ratio for pre-wetting.
Pour ratio for each pulse
We recommend a 1:5-1:7 ratio for each pulse to make sure that all the grounds are saturated and evenly agitated.
We recommend 18g for Hario V60/01, 22g for Hario V60/02, 20g for Kalita Wave 185 and 15-20g for Fellow StaggX. Dose up with the same brew ratio if there is channeling or choking in the brew, especially when it’s weak or lacking in flavors. Dosing also affects your pour height significantly. We recommend higher pour height for larger dose and vice versa to dig the ground bed appropriately, hence your total pouring time is usually almost same for every dose. Your main variables for different doses are not pour time but pour rate/height.
It is said that appropriate water hardness for coffee brewing is 60-130 ppm. If your tap water is out of the optimal range, we recommend Volvic for brewing water. Try softer water when your coffee is too heavy, lacking in flavors or bitter. On the other hand, brewing with harder water when your coffee is sour, lacking in sweetness, or weak.
Kettle Stream Theory: Coffee Ad Astra
The Rao Spin: Mr. Scott Rao
See the collection below to try our brew methods!!