Help with coconut liqueur. How much syrup!?

[Rocafire]

I'm making a rum coconut liqueur starting from a base of 500ml of 96% ethanol, a classic base for liqueurs. I choose it just to pull more flavours out (and making it "shelf stable" since all the recipes I've found for some reason either sous vide a 70% rum for hours or use it just straight and leave the maceration doing her work, with some even explicitly saying that this was the reason they were doing it or using it why) from shredded coconut, few cacao nibs and a vanilla bean that I will macerate in it for a week. Now my question is, since after 7 days of maceration I will cut this 96% solution with 700ml of a 47% rum (veritas or probitas if you are in the US) bringing the whole solution to an average of 67,4%, with HOW MUCH syrup (i will use a ratio of 1:1 water to a demerrara sugar) do I have to cut it with to bring it between 25 and 30% ? I'm seeing way too many different "for 100ml of rum add x of water and y of sugar", it feels like i'm going dumb. Expecially if some results are 450ml of syrups and others are 1.4L of it. It just seems to be all over the place.
Short version: I have a mix of 500ml of 96% coconut infused alchool + 700ml of probitas/veritas (47%) resulting in 1,2L at 67,4%. With how much syrup should I cut it to bring it between 25 and 30%?
Thanks to everyone that will help me

[Steve Broady]

If you’ve already got your sugar dissolved into water to form a syrup, then it’s not likely to change volume a great deal when you add alcohol. For the purpose of ABV calculations, I’d pretend that it’s an equal quantity of water.

Thus, if you want to bring 1.2L of 67.4% down to 30%, you’ll need 1.51L of something that doesn’t contain alcohol. Could be water, could be syrup, could be fruit juice, etc.

To get to 25%, you’ll need 2.05L. So I’d say that anywhere between 1.5-2L should give you the results you want.

I used an app called DistillersCalculator for this. Other calculators may vary slightly, but I doubt they’ll be too different.

[SW_Shiner]

If you click the still in the top left of this page, it willl take you to the home site. Under the word Home in the header, is a button labeled calculators. Clicking that will take you to another page. About half way down, there is Calcs from Rad14701. There are some dilution calcs there that should help.

[NZChris]

Decide on your finished abv.

Calculate your total volume of pure alcohol, then calculate the finished volume when diluted to that abv.

Decide on your finished weight of sugar, often expressed as g/100ml.
If you don't know what it should be, do research to find out, e.g., what is the g/100ml of a liqueur that you know you like?

Calculate how much sugar you need in your finished volume.
Make a simple sirup using that amount of sugar.

Mix the alcohol and sirup in a measuring vessel and make it up to the calculated final volume with water.

Or;
If you already have simple sirup, use its g/100ml to calculate how much to add.

[Rocafire]

Thank you very much!
Yeah most results were in between 1.2 and 2L but few of them were under 500ml. That's what threw me off

If you’ve already got your sugar dissolved into water to form a syrup, then it’s not likely to change volume a great deal when you add alcohol. For the purpose of ABV calculations, I’d pretend that it’s an equal quantity of water.

Thus, if you want to bring 1.2L of 67.4% down to 30%, you’ll need 1.51L of something that doesn’t contain alcohol. Could be water, could be syrup, could be fruit juice, etc.

To get to 25%, you’ll need 2.05L. So I’d say that anywhere between 1.5-2L should give you the results you want.

I used an app called DistillersCalculator for this. Other calculators may vary slightly, but I doubt they’ll be too different.

[Rocafire]

Oh ok, I think I got it now. So let's say after maceration the whole result is 1L at 67%. My liqueur of choice has a 250g/1000ml of sugar (this is for limoncello for example) . Now, let's say that to dilute it at 30% i need 1L of water, I need to add 250g×2000ml so 500g of it right?

Decide on your finished abv.

Calculate your total volume of pure alcohol, then calculate the finished volume when diluted to that abv.

Decide on your finished weight of sugar, often expressed as g/100ml.
If you don't know what it should be, do research to find out, e.g., what is the g/100ml of a liqueur that you know you like?

Calculate how much sugar you need in your finished volume.
Make a simple sirup using that amount of sugar.

Mix the alcohol and sirup in a measuring vessel and make it up to the calculated final volume with water.

Or;
If you already have simple sirup, use its g/100ml to calculate how much to add.

[Rocafire]

Thank you!

If you click the still in the top left of this page, it willl take you to the home site. Under the word Home in the header, is a button labeled calculators. Clicking that will take you to another page. About half way down, there is Calcs from Rad14701. There are some dilution calcs there that should help.

[NZChris]

1l at 67% = 670ml alcohol

670ml alcohol makes 2233ml at 30% abv, (670/0.30)

Sugar required for 250g/1000ml = 558g, (2233*0.25)

Water to add is however much it takes to top up the liqueur to 2233ml

[Rocafire]

Oh ok, thank you very much!!

1l at 67% = 670ml alcohol

670ml alcohol makes 2233ml at 30% abv, (670/0.30)

Sugar required for 250g/1000ml = 558g, (2233*0.25)

Water to add is however much it takes to top up the liqueur to 2233ml