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Thread: Espresso Brewing Formula and why you should know it.

  1. #1
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    Espresso Brewing Formula and why you should know it.

    Measuring coffee by volume is inconsistent because as coffee ages, the amount of crema also varies. Typically we define an extraction by saying something like 30 mL in 25 seconds or 30 mL in 20 seconds. In science this is known as a volumetric flow rate, i.e. change in volume over change in time. For espresso the units would be in mL/s. This is highly inaccurate due to the fact that a volume reading is typically done by eyeballing in a graduated shot glass, which is inaccurate by its very nature.

    Mass is a much more reliable unit to measure our extractions. We could perhaps use a mass flow rate, i.e. change in mass over change in time for the espresso in our demitasses, leading to a measurement in grams/s. However, volumetric flow rates and mass flow rates doesnt give us much insight to the extraction were trying to describe. We need other pieces of key information such as dosage and espresso mass. In other words, describing our espresso in terms of flow rates is useless. Enter the Espresso Brewing Formula.

    The Espresso Brew Formula or EBF is a ratio of the mass of ground coffee to the mass of the brewed espresso.

    EBF (%) = 100 * (dosage in grams)/(espresso mass in grams)

    What the EBF does not specify is grind setting and hence extraction time, like the volumetric flow rate. This however can be recitfied by appending such information on top of the EBF. This would then almost fully describe an extraction of espresso for the purposes of CS members sharing information and seeking assistance.

    eg: EBF (%) = 60 % - 18 gram dose, 30 gram espresso, 22 second extraction, 92 degrees C. Another person trying to replicate your extraction has almost all the information they need to try and achieve a similar extraction.

    I like drinking my espressos anywhere between 55-62 % EBF. 65% and above is ristretto range - underextracted sour coffee.

    To end this post, for those of you who are asking for assistance in trying to diagnose your extractions, please fully describe your extraction by specifying:

    1) Dosage - how much coffee you put in the basket in grams
    2) Espresso mass - how much the resulting liquid espresso weighs in grams
    3) Extraction time - from the time you engage your pump to the time you turn it off in seconds
    4) Temperature - if known
    5) Roast date - if known

    Volumetric flow rates will not help e.g. 25 mL in 30 seconds.

    Your thoughts and comments are more than welcome. I hope we can change the way we talk about coffee by eradicating the use of volumes.

  2. #2
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    Re: Espresso Brewing Formula and why you should know it.

    Quote Originally Posted by 1F292A283F2929350939323535365A0 link=1332221851/0#0 date=1332221851
    I like drinking my espressos anywhere between 55-62 % EBF..
    haha can you flesh this out a bit please? what dosage mass, espresso mass, temp etc for your ideal espresso? (you broke your own precedent before it even started~!) :P

    EBF based purely on mass percentage seems weird... ie
    8 grams beans producing 16 grams liquid and 16 grams beans producing 32 grams liquid would both have the same EBF, but they would taste very different in the cup; no?

    id been meaning to ask in another thread but might as well here: different people have different views on starting their timing including or not including pre-infusion time... for whatever reason different machines ive tried seem to preinfuse for different times (+/- 5 seconds!); whats the theory behind starting from pump engage and not from any other point? (ie first drops, or when pump hits full pressure)

    to qualify on my current machine i currently have settled on dose of ~15g and i get 30 mls = 53% EBF.
    beans are 17 days old.
    dont have extraction temp.
    if i get it all right this takes ~35 seconds, but my machine preinfuses for a good 9+ seconds... am i on the right track? this has given me the best taste in the cup so far.

  3. #3
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    Re: Espresso Brewing Formula and why you should know it.

    Quote Originally Posted by 7C7A67716A677139313038080 link=1332221851/1#1 date=1332225611
    haha can you flesh this out a bit please? what dosage mass, espresso mass, temp etc for your ideal espresso? (you broke your own precedent before it even started~!)*
    HA! Well thats the range of EBF I enjoy my espressos at. Specifics would change blend to blend.

    Quote Originally Posted by 7C7A67716A677139313038080 link=1332221851/1#1 date=1332225611
    8 grams beans producing 16 grams liquid and 16 grams beans producing 32 grams liquid would both have the same EBF, but they would taste very different in the cup; no?
    Its quite possible! EBF is a ratio. You could infinitely keep scaling up provided you had a big enough espresso machine! Tastes would could be different which is why you never specify an EBF on its own. You would give additional information regarding dosage and mass of espresso etc. When I make espresso, it is usually with a double, so EBFs I talk about are for doubles - Im well aware youre not mind readers, but a good proportion of CSers produce espresso from a double basket. I dont think there would be a dramatic difference in taste between an EBF for a single and a double (I havent tried this yet!). They would share similar characteristics. I typically find espressos made from a single more pleasing.


    Quote Originally Posted by 7C7A67716A677139313038080 link=1332221851/1#1 date=1332225611
    id been meaning to ask in another thread but might as well here: different people have different views on starting their timing including or not including pre-infusion time... for whatever reason different machines ive tried seem to preinfuse for different times (+/- 5 seconds!); whats the theory behind starting from pump engage and not from any other point? (ie first drops, or when pump hits full pressure)
    I dont preinfuse as I dont like wasting time, so I take it from the time the pump is engaged to the time it is turned off.

    Quote Originally Posted by 7C7A67716A677139313038080 link=1332221851/1#1 date=1332225611
    am i on the right track? this has given me the best taste in the cup so far.
    I think youve answered your own question!

  4. #4
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    Re: Espresso Brewing Formula and why you should know it.

    I like the concept of EBF for the reasons stated, (however for me having to weigh the shot requires getting over the same sort of mind-sets as having to weigh the grinds).

    For us lever machine owners some of the other parameters might be different as my machine doesnt have a pump, but Im sure appropriate brief notes could accommodate this.

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    Re: Espresso Brewing Formula and why you should know it.

    Really.....???? I am sure that there is a very complex science to every aspect of coffee, from the growing of a seed to the making of a cup......and everything in between.

    But, here is my second crack worth - all of which I have learned here in the last 4 months.
    1. Keep your machine clean.
    2. Have fresh beans.
    3. Get your volume right.
    4. Get your grind right.
    5. Tamp firmly, evenly and consistently.
    6. Practice a lot.

    Hey presto!!!! You have just turned a very complex lot of chemistry (both procedurally and chemically) into a delicious art form for all to enjoy.
    Its coffee....just drink it. ;)

    Enjoy.

  6. #6
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    Re: Espresso Brewing Formula and why you should know it.

    Question:

    What is the weight difference between 30ml of espresso and 30ml of water?

    As if there is negligible difference all your doing is measuring the water by weight since 1ml = 1g.

    So really the formula just becomes dose vs shot length.

  7. #7
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    Re: Espresso Brewing Formula and why you should know it.

    Weigh your shots and find out.
    The creama is an inconsistent, therefor shot volume changes

  8. #8
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    Re: Espresso Brewing Formula and why you should know it.

    Quote Originally Posted by 507C7F7A7D4C44130 link=1332221851/6#6 date=1334282378
    Weigh your shots and find out.
    The creama is an inconsistent, therefor shot volume changes
    If you include the creama in your shot volume, do you have a formula for.."% creama".. or "Ideal creama to liquid Ratio".. ??
    ..Or is a shot with more creama than liquid acceptable ? ( accepting that some creama is desirable )


  9. #9
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    Re: Espresso Brewing Formula and why you should know it.

    Behmor Brazen - $249 - Free Freight
    More creama than liquid in my limited expirence is due to beans that are to fresh.
    I have no formula for creama % but I weigh total shot

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