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# Basic Maths Calculation Question

edited November 2018
1. If I need 60ml of flavour added to 1litre of my gin @ 37.5% to get it to the flavour I want it at.. I then have 1060ml at what ABV? (I used an online calc and got 35.39% - but whats the math? And is that correct?)
2. If I now have flavoured gin of 1060ml at 35.9%, how much gin at 37.5% do I add to the now flavoured gin to take it back to 37.5%?

Or am I overthinking it? Can I just get it to the flavour I want and then add more gin until it has 37.5% again, using my calibrated Stevenson Reeves hydrometer?

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• Is the flavoring EtOH based? If so, that will need to be factored into the calculations.

• no thankfully... propylene glyco

• edited November 2018

Forget trying to hit proof by volume.
Always use mass (weight).
Use volume at the end when bottling.

I use this for calculations when mixing and proofing:
Alcohol amount in the aqueous alcohol solution @ PLANETCALC

Also there is AlcoDens.

Use a pretty accurate alcometer like the ones with a low range. I have 35-70 and 70-100.
You can go much finer than that even with a range of just 10%.

You can then convert this to ABW depending on the temp. Then you can work out the ethanol mass in grams based on the weight of your liquid.

Means you can get it right first time.

I used to mix based on volume. Just really error prone.

I did a gin test run today. Everything was done by mass. I was aiming for 41% ABV (hearts was 74%) and after diluting I'm absolutely spot on.

Based on density I reckon I have 8 litres (7920ml to be precise :) )

Also why not add the flavour to the hearts and then dilute to final proof?

• If it is ok to use my hydrometer (low range 31.7 to 35 iirc) to measure.density with flavouring in it hen I'm fine with the rest of it.

• edited November 2018

How much PG is in your flavoring? Do you have the breakdown?

Assuming 100% PG - that amount in your mixture - 580 grams per 100ml, puts you firmly into proof obscuration territory, meaning your hydrometer is not capable of accurately gauging proof without correcting for the level of obscuration.

• edited November 2018

Your hydrometer (if it is an alcometer) is only accurate when the mix is ethanol and water.

• It is an alcometer, it only measures density.

I am not yet sure how much flavour I will be adding per litre of product, i think it will be around 5ml.. but I will know more tomorrow.

• Propylene Glycol based flavor. Each to their own i guess

Is this common ?? Will you write its inclusion on your bottle ingredients ?

• My problem is I am just starting out and trying to find as natural an ingredient as possible, I will ask the supplier for an ethanol based flavour if that's a better option? But NO I hadn't planned on putting ingredients on the label. Id be eternay grateful for any direction given.

• edited November 2018

I honestly would not know about whats available though i would think you should be able to get whatever flavor profile you want from a combination of vapor infusion and maceration of base herbs and spices.

I do know they use this stuff in ice cream but they also used whale blubber in it years ago ( at least its natural ). I would imagine Grim will know more about PG use - but to me it is a foreign unnatural substance best left in the lab.

There are a number of people sharing their exact procedures in The Big Gin Thread ( me included ) which will give you a good starting point and you will end up with a reasonable product of which you can expand on. You have to start somewhere and chucking in concentrates does not seem to be the way to go. If you want concentrates buy a glass lab still for bugger all money on eBay and make your own. That way you can doctor any product you make and in the process learn flavors / tastes etc. And its all your own work.

Just my opinion.

• Having tasted a lot of flavoured gin in the UK i am sure than 95% of producers are NOT getting flavour from fruit or herbs.. some of them are so strong in flavour it would not be commercially possible. I have tried to extract flavour from rhubarb at 500gm of fruit per litre of finished product it didnt have a fraction of the rhubarb flavour that a well known commercial gin did.

I would love to take flavour from base fruit but i have tried and it doesnt seem viable.

• and further to this 95% (made up number) of consumers just don't care...

• back to the question.. can I proof my flavoured gin using my alcometer? if the flavour added makes up a very small proportion of the volume, say 5ml per litre?

if the PG is going to throw it off I could have the flavour suspended in EtOH..

• edited November 2018

Work by weight, gauge your gin immediately prior to proofing. Treat the 5ml per 1l volume of flavor as if it were water when you add water to get to your target weight/proof. Make sure your initial gauging figures are extremely accurate and precise, as checking your proof after flavor is added will introduce obscuration and error. If you attempt to regauge and reproof after you add flavor, you'll likely make a bigger mess.

To check, you'll need to proof by obscuration/evaporation. I know your not in the US, but the TTB videos are a good resource on the lab methodology:

Distilled Spirits - Frequently Used Proofing Processes @ TTB

The flavor manufacturers should be able to provide you with an accurate composition of the flavoring. If you have this, you can actually work backwards to determine the proof impact.

• edited November 2018

For example, assuming 5ml of your flavor is 100% propylene glycol (unlikely but just using the number), that's 4.8 grams per 1000ml, or 0.48g per 100ml. I know this because I know the density of propylene glycol.

Multiply this number by 4 to get the proof obscuration, in this case it would be 1.92 proof.

Add this to the apparent (measured proof) to get the true proof.

So, if your target proof is 80, you hydrometer should be reading 80 proof - 1.92 proof or 78.08 proof.

If you were to correct this to 80 proof by adding more undiluted gin, you'd be very wrong.

• edited November 2018

Also realize, you can redistill your liquid flavoring if what you are looking for is only the volatile constituents. This does not work for all flavors, since there are components of certain commercial flavors that are not volatile. This makes it easy to dispense with the solvent/carrier (in this case glycol) used to carry the flavor.

• edited November 2018

thanks @grim - that's some very useful information.

before proofing work out how much water i need to add to get to my target proof - using weight and temp corrected alcometer reading

lets say i need to add 15 litres of water to get to my target of 43%

figure out how much flavour i would need for the final product - lets say 150ml

add 14.85l of water and 150ml of flavour - done!

further - i can check the end result by subtracting the proof obscuration from the end proof.. 100% glycol is 4 x 0.48 so i subtract 1.92 (or the % should be .92% less at 42.04% - again using alcometer density and temp correction)

But my flavour will not be 100% and the manufacturer should be able to tell me the overall composition.

HOWEVER if my flavour is made up of only volatile compounds i should be able to either add it to the boiler or the vapour path and carry it over and this would negate the need for proof obscuration.

• On 15 Nov you spoke of 60 ml of flavour per litre of gin, but later you used 5 ml per litre. I assume 5 ml per litre (0.5% by volume) is correct.

If adding the flavouring drops the ABV below 37.5% no quantity of more 37.5% spirit will ever get the ABV back to 37.5%. You need high strength GNS to do this.

In 1000 ml of spirit at 37.5% ABV there is 375 ml of pure ethanol. If you add 5 ml of flavouring the 1000 ml will increase in volume. The question is: by how much will it increase?

If we add 5 ml of pure ethanol to 1000 ml of water we know the volume will not increase by 5 ml, but there is plenty of data available to tell us what it will be (1004.78 ml according to AlcoDens). We do not have that data for PG plus alcohol and water.

But it is likely that your flavouring will increase the volume by between 4.5 and 5.5 ml, so the total volume will be between 1004.5 and 1005.5 ml. We know that if there was no alcohol in the flavouring the total alcohol is still 375 ml. The ABV is therefore between 37.33 (= 100x375/1004.5) and 37.29 (= 100x375/1005.5).

You can achieve this fairly tight level of accuracy because the GNS and water have already been mixed to create the 37.5% ABV spirit and the bulk of the shrinkage has already been taken into account. If you want to go directly from GNS plus water and flavour then you need something like AlcoDens LQ - provided there is little or no PG present.

I don't know that PG would follow the TTB's obscuration rule of thumb. That is for solids like sugar and it may not apply to PG. You flavouring is also unlikely to be pure PG.

• 60ml was concentrate cherry, 5ml is extract.. still figuring it out.

good plug for alcodens ;-) - forum discount?

• edited November 2018

@needmorstuff said: good plug for alcodens ;-) - forum discount?

Why not? The interwebs are full of Black Friday offers at the moment. Use the code "STILLDRAGON" on the AlcoDens or AlcoDens LQ order pages to get a 20% discount. Valid until 30 November 2018.

Note to Moderator - please delete this post if it is not allowed here. Thanks

• Good stuff mate.

StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

• Offering recipe advice on forum replies for me is always a bit of a faux pas.

However...

I would really advise you stick to natural ingredients. Forget artificial ingredients.

If you cannot make gin from natural (dried or fresh) ingredients then don't bother.

We are the opposite of Big Alcohol, right?

I looked at making a rhubarb based gin last month. The rhubarb in our local supermarkets gets really bad reviews so I knocked it on the head. If I cannot make it from real ingredients, there's no point.

• the ingredients although extract do claim to be either natural or organic to date.. none of them have been a manufactured chemical.

i tried the same with rhubarb.. not enough flavour - that's what got me down the road of natural extracts.

i am the opposite of big alcohol but i need a viable protocol and laying my hands on cherries and then trying to replicate an extraction process isn't viable either... same would go for any fruit.

sad thing is I dont even like flavoured gins.. this is all for the consumer. i would tip them all in the toilet, it is starting to frustrate me now.

• Concentrate on the white spirits first.

Then work on post-distilled flavours.

I have zero intention of launching with fruit flavoured gins. My fruit flavoured gin R&D is looking 18-24 months into the future.

If the market rejects my white spirits then no pink gin for me.

• I am certainly starting to think that way! walk before running and all that

• You got an all rounder dry gin?

Any other dry gins? Spiced, floral etc?

• just the dry, i would say it is spice and citrus forward though.. it's ready - we just wanted to come to market a flavoured one also.

• @needmorstuff said: Having tasted a lot of flavoured gin in the UK i am sure than 95% of producers are NOT getting flavour from fruit or herbs.. some of them are so strong in flavour it would not be commercially possible. I have tried to extract flavour from rhubarb at 500gm of fruit per litre of finished product it didnt have a fraction of the rhubarb flavour that a well known commercial gin did.

I would love to take flavour from base fruit but i have tried and it doesnt seem viable.

You either want to make a "real" product that reflects the attributes people would associate with the natural product or you want to create the artificial lab synthesized product the majority of the brainwashed public expect.

A great example of this is cherry. Many have an impression that cherry should taste like Dr Pepper or cough syrup...so when they taste a natural extract they get nothing of the sort. Your job is to educate and create the best product possible that showcases your landscape...otherwise...you're competing with laboratories to synthesize flavours...

• i'm listening fellas/gals. how long do we think it would take to steep cherries in gin to extract flavours? weeks/months? and I am thinking best prior to proofin... but then how does one proof after steeped in cherries..

the pull to get to market is strong but I hope the honesty to the craft is stronger.

• edited November 2018

Don’t poo poo all the flavor houses in one fell swoop. There are plenty that are every bit as craft and would put most of us to shame with regard to their level of sophistication and maturity. Technique and science regarding flavor manufacture and distilling beverages has more in common than not, especially the production of gin.