After my post V60: Drip or Immersion on VST Coffee Tools? questioning which settings to use on the VST App, I thought i’d take it one step further and develop a calculator that would allow users to work out the settings for their particular brew method.
You can find the calculator here. This calculator works best for Pour Overs and Batch Brewers. It allows you to pop in the particulars of your brew and it will spit out an Adjusted LRR that will give you the most accurate EXT %.
All you need to do is prepare a brew using your technique and measure the following:
Dose (g) – Mass of the dry grounds in grams.
Brew Water Weight (g) – The weight of the water you are starting with. This calculator is assuming its at 90+ degrees, similar to the app.
Beverage Weight (g) – The weight of the final beverage.
Beverage TDS (%) – The TDS first part of the beverage
End portion TDS (%) – as you get to the end of your brew, capture the last 5-10g or so to come through and take a measurement using the Refractometer.
End Weight (g) – The weight of the last part of the brew that was captured.
From these numbers the calculator will work out the Adjusted LRR. You then place the Adjusted LRR into the app under Drip Mode replacing the default 2,1. When you place this Adjusted LRR into the app it will give you an Extraction Yield % that is now accurately taking into account the extracted coffee that still remains in the coffee bed. Both MOIST and CO2 should be returned to Zero, in my view if you can’t measure it you may as well leave it at Zero.
Feel free to shoot across any questions.