# Ext yield in coffee tools **URL:** \ **Category:** Q&A\ **Created:** [January 6, 2018, 11:48am UTC](https://baristahustle.discourse.group/t/ext-yield-in-coffee-tools/2283 "2018-01-06T11:48:06Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![ClausD](https://avatars.discourse-cdn.com/v4/letter/c/e9c0ed/32.png) [@ClausD](https://baristahustle.discourse.group/u/ClausD)\ **Post date:** [January 6, 2018, 11:48am UTC](https://baristahustle.discourse.group/t/ext-yield-in-coffee-tools/2283/1 "2018-01-06T11:48:06Z")
so in VST coffee tools / espresso mode. Calculation of extraction yield i believe is Brewed coffee x TDS℅ / ground coffee dose . For instance 40 g x 10(tds%) / 20( dose) = 20 % yield . How come coffee tools(espresso mode) come out as 20.73 % ?? What parameter am i missing ? ![IMG_20180106_124016](https://canada1.discourse-cdn.com/flex027/uploads/baristahustle/original/2X/8/842aab38b350528bbe7ca0f125786f90ef352906.png) ---
**Author:** ![MWJB](https://avatars.discourse-cdn.com/v4/letter/m/da6949/32.png) [@MWJB](https://baristahustle.discourse.group/u/MWJB)\ **Post date:** [January 6, 2018, 1:43pm UTC](https://baristahustle.discourse.group/t/ext-yield-in-coffee-tools/2283/2 "2018-01-06T13:43:53Z")
It’s only 20%EY if there is no moisture or CO2 in your coffee dose. Note values for CO2 0.5% & MOIST 3% on right hand side. Moisture in roasted coffee is well established & discussed in many papers going back to 1953 at least (Schwartzman), CO2 parameters are discussed in Illy’s book, for example. In dehydration (the datum for coffee tools), it’s a good idea to establish how much of your soluble material is ‘something else’. In terms of consistency, it doesn’t much matter whether you leave the pre-sets as they are, or set to “0” (or adjust either to add up to 3.5% total), but as you seem to trust the software, you might assume that these values were decided upon for good reason. ---
**Author:** ![ClausD](https://avatars.discourse-cdn.com/v4/letter/c/e9c0ed/32.png) [@ClausD](https://baristahustle.discourse.group/u/ClausD)\ **Post date:** [January 6, 2018, 2:04pm UTC](https://baristahustle.discourse.group/t/ext-yield-in-coffee-tools/2283/3 "2018-01-06T14:04:43Z")
Ahh ofcourse … Dohh… . thanx Mark 🙂 Did not give it a thought in terms of consistency… Was just curious as to what i was missing in the equation 🙂