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  1. #1

    Default Dilute by volume or dilute by weight?

    Hi - Annoying newbie here. I know, I know the correct answer is "dilute by weight." I have my balance at the ready to use for the first time - but how?

    Here's my issue. I want to make a bunch of 20% dilutions of my raw materials for blending. I have a Siam Benzoin already diluted to 50% in alcohol, and I want to take it to a 20% dilution in alcohol.

    A little searching revealed the C1V1=C2V2 formula, where C=Concentration, and V=Volume. So by this formula, if I want to end up with 5 ml of solution at 20% concentration, then I need to add 2 ml of the 50% solution to 3 ml alcohol to end up with 20% dilution. I also found a helpful calculator here: http://www.physiologyweb.com/calcula...y_percent.html

    But how do I calculate this if I am doing it by weight / in grams? Since the formula is based on volume, I'm assuming it doesn't work the same way.

    And if I am doing a straight up dilution of a material at 100% concentration - is it as straightforward as it seems? Like, to get to a 20% dilution do I just do 1 gram raw material + 4 grams alcohol = 5 grams solution at 20% dilution? Do I need to be factoring in molecular weight or anything (horrors, please say NO.)

    Thanks for any help! The former English major kisses the feet of any Chemists/math people.
    Wesley Hall Parker
    idreamofperfume.com

  2. #2
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    Default Re: Dilute by volume or dilute by weight?

    Weigh an empty bottle.
    Pour the 50% benzoin into it and weigh it.
    Divide the weight in half.
    Multiply that half X three.
    Add that amount of alcohol or dilutant to get a 20% dilution.


    PK
    Paul Kiler
    PK Perfumes
    http://www.PKPERFUMES.com
    Gold Medal for "Best Aroma"; Los Angeles Artisan Fragrance Salon

  3. #3

    Default Re: Dilute by volume or dilute by weight?

    Yes it's as simple as 1 gm of material + 4 gm alcohol = 20% dilution. Don't forget to tare the scale after placing the empty bottle on it but do not tare after placing the material in it.

  4. #4

    Default Re: Dilute by volume or dilute by weight?

    Thanks PK and ID!

    I get the straightforward approach (where you tare the bottle first). Also, if any other newbies are looking for tips on creating a simple dilution starting with a 100% concentrated material, Chris from Pell Wall Perfumes wrote a nice tutorial here:
    http://pellwall-perfumes.blogspot.co...-blending.html

    As for getting from a 50% solution to a 20% solution....(y'all bear with me, math is not my natural gift)...Paul, it looks like you are employing the same formula I used above, just swapping out weight for volume.

    So, C1W1 = C2W2, where C=concentration and W=weight. So, for example, if I have a 50% Benzoin solution in alcohol and want to get to a 20% solution - I can decide I want to end up with a final weight of say...5 grams.

    C1= 50% = .5
    W1 (weight of 50% solution to add) = unknown
    C2 = 20% = .2
    W2 (desired final weight of 20% solution) = 5 grams

    .5W1=.2(5grams)
    .5W1=1 gram
    W1= 2 grams

    So we know I need to add 2 grams of 50% Benzoin.
    Since I want to end up with a final weight of 5 grams, then 5-2 = 3 grams.
    So I add 3 grams alcohol.

    Seems to work and matches the outcome of Paul's method above.

    If anyone checks my math and finds an error, please let me know! I just wanted to get to a formula so I could reproduce this with any dilution-to-dilution conversion. Thanks all!
    Last edited by pussinboots; 3rd July 2015 at 05:32 PM.
    Wesley Hall Parker
    idreamofperfume.com

  5. #5

    Default Re: Dilute by volume or dilute by weight?

    Hi all, I apologise if this has been answered before, I did try search but didn't come across this specifically. I know if I'm diluting stronger raw materials we generally work by weight, but when we are making final large batch of fragrances and are ready to mix the compound with alcohol at 15% concentration, do I do this by weight or by volume?
    I feel like I would need a scale that goes well over what mine does (1.5kg) if it needs to be done by weight.
    Thank you!

  6. #6

    Default delete

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    Last edited by julian35; 6th December 2017 at 01:12 AM.

  7. #7
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    Default Re: Dilute by volume or dilute by weight?

    Quote Originally Posted by TheScentOfThis View Post
    Hi all, I apologise if this has been answered before, I did try search but didn't come across this specifically. I know if I'm diluting stronger raw materials we generally work by weight, but when we are making final large batch of fragrances and are ready to mix the compound with alcohol at 15% concentration, do I do this by weight or by volume?
    I feel like I would need a scale that goes well over what mine does (1.5kg) if it needs to be done by weight.
    Thank you!

    Yes, Dilute by weight.

    larger qty scales are not so sensitive or expensive. I have two scales, one for up to 100g, and the other to 5kg.

    20160811_083421 small.jpg
    Paul Kiler
    PK Perfumes
    http://www.PKPERFUMES.com
    Gold Medal for "Best Aroma"; Los Angeles Artisan Fragrance Salon

  8. #8
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    Default Re: Dilute by volume or dilute by weight?

    This is a very handy dilution ratio chart for weight dilution.
    Dilution Ratio target chart.jpg
    Paul Kiler
    PK Perfumes
    http://www.PKPERFUMES.com
    Gold Medal for "Best Aroma"; Los Angeles Artisan Fragrance Salon

  9. #9

    Default Re: Dilute by volume or dilute by weight?

    Quote Originally Posted by pkiler View Post
    Yes, Dilute by weight.

    larger qty scales are not so sensitive or expensive. I have two scales, one for up to 100g, and the other to 5kg.

    20160811_083421 small.jpg
    Thank you pkiller, this is very helpful, handy chart too! I don't know what I would do without the Basenotes folks!

  10. #10

    Default delete

    deleted
    Last edited by julian35; 6th December 2017 at 01:12 AM.

  11. #11
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    Default Re: Dilute by volume or dilute by weight?

    You can dilute by weight using volume if you don't mind doing a little math. You need to adjust for the fact that the specific gravity of ethanol is 0.787. That means that 1 ml of ethanol weighs only 0.787 g instead of the 1 g that 1 ml of water would weigh. So, if you know how many grams of ethanol you need (per PK's chart) you can divide that number by 0.787 to determine how many mls (= ccs) you need.

  12. #12
    Super Member Godmu's Avatar
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    Default Re: Dilute by volume or dilute by weight?

    Quote Originally Posted by Toujours Mink View Post
    You can dilute by weight using volume if you don't mind doing a little math. You need to adjust for the fact that the specific gravity of ethanol is 0.787. That means that 1 ml of ethanol weighs only 0.787 g instead of the 1 g that 1 ml of water would weigh. So, if you know how many grams of ethanol you need (per PK's chart) you can divide that number by 0.787 to determine how many mls (= ccs) you need.
    but does this not mean you have to know the specific gravity of the "oil" you need to dilute as well?
    'Today I'm a star. What will I be tomorrow? A black hole?'
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  13. #13
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    Default Re: Dilute by volume or dilute by weight?

    To be perfectly correct, yes. You can look them up at The Good Scents Company.

  14. #14

    Default Re: Dilute by volume or dilute by weight?

    Quote Originally Posted by Godmu View Post
    but does this not mean you have to know the specific gravity of the "oil" you need to dilute as well?
    Maybe not? If you know the weight of the perfume material you want to dilute, then calculate the weight of the alcohol you need to add to bring the product to your desired dilution. Then use the specific gravity of alcohol to calculate the volume that the needed weight of alcohol will take up. Measure out that volume, then add it to your concentrate. Don't assume that x millilitres of your concentrate plus y millilitres of your diluent will result in x plus y millilitres of mixture.

    I don't recommend this, but it seems feasible. Happy to be corrected.

  15. #15

    Default Re: Dilute by volume or dilute by weight?

    Quote Originally Posted by pkiler View Post
    This is a very handy dilution ratio chart for weight dilution.
    Dilution Ratio target chart.jpg

    This chart is a good reference. Thanks

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