Suggestions on how to de-color without changing aroma?

[LegadoOrganicDistillery]

I thought I'd use the hive mind for this question - 

We have a client that wants a very specific blend of our rums.  It is 97% fresh column rum and 3% rum aged 3 years.  The resulting blend has a very nice aroma and flavor profile that they approved, but after approval, they asked if we can de-color as it does have a yellow-gold color.  Well, the client is always right so...

We used our activated carbon filter and gravity filtered the blend.  It took 3 passes, but the resulting liquid was as clear as water (and very smooth).  While the customer was happy with the transparency, they did not approve the sample because the aromas changed (well....duh!)

Anyhow, any ideas on how to filter out color without changing aroma?  Or, how to add the aromas back in?  We are going to do a rum essence of the aged rum in our rotovap to see if we can dose the aroma and flavors back into the filtered spirit....I don't have high hopes for that approach, but have to try.

Any other ideas?

 

Thanks!

[Silk City Distillers]

You need to use a carbon that’s almost exclusively high mesopore.  This is probably going to be a wood based carbon, powdered, and steam activated.  Color molecules are large, flavors are small.  Use an off-the-shelf carbon and you’ll remove more flavor than color.

You are going to need to do bench trials to determine both the grams/liter dosing rate, and the treatment times.  You need to balance these two variables.  The more you dose, the faster you remove the color, but the more challenging to filter.  Dose too little and you may not hit your target color, which will require starting over, and it will have flavor impacts if you need to repeat.

You are going to need to be sure you can filter out the powdered carbon from your spirit at scale, because to dose it, you’ll be pouring your powdered carbon directly into your spirit, mixing the slurry, and then filtering.  Your total treatment time, including filtering, needs to match your bench trial target times.  This is critical.  Get it wrong and you’ll ruin the batch.

Your filtration needs to be able to carry the full volume of your dosed carbon.  You may need a large plate and frame or other large capacity filter.  You will require sub-micron final filtration to polish and remove carbon fines.  When you are done your filters will be caked with mud.

I would decolorize the aged spirit alone in this case, then blend.  Do not shoot for pure white in this case, as further dilution will lighten the color.  It will be easier to partially reduce the proof before filtering.

[Silk City Distillers]

A good starting point for bench trials is 5 grams a liter for darker aged spirits, 2.5g/l for lighter aged spirits.  This will give you a good idea why the holding capacity of the filtration is important.  A 500 liter batch of spirit might require 1.2kg (2.7lb) of PAC.  

I've decolorized bourbon using this method, just to screw with peoples heads by pouring them a glass of ice-clear bourbon.

[LegadoOrganicDistillery]

18 hours ago, Silk City Distillers said:

You need to use a carbon that’s almost exclusively high mesopore.  This is probably going to be a wood based carbon, powdered, and steam activated.  Color molecules are large, flavors are small.  Use an off-the-shelf carbon and you’ll remove more flavor than color.

You are going to need to do bench trials to determine both the grams/liter dosing rate, and the treatment times.  You need to balance these two variables.  The more you dose, the faster you remove the color, but the more challenging to filter.  Dose too little and you may not hit your target color, which will require starting over, and it will have flavor impacts if you need to repeat.

You are going to need to be sure you can filter out the powdered carbon from your spirit at scale, because to dose it, you’ll be pouring your powdered carbon directly into your spirit, mixing the slurry, and then filtering.  Your total treatment time, including filtering, needs to match your bench trial target times.  This is critical.  Get it wrong and you’ll ruin the batch.

Your filtration needs to be able to carry the full volume of your dosed carbon.  You may need a large plate and frame or other large capacity filter.  You will require sub-micron final filtration to polish and remove carbon fines.  When you are done your filters will be caked with mud.

I would decolorize the aged spirit alone in this case, then blend.  Do not shoot for pure white in this case, as further dilution will lighten the color.  It will be easier to partially reduce the proof before filtering.

Thanks for the well thought out answer!  Being in Paraguay, access to a wide variety of activated carbon can be challenging, but we´ll start the hunt!  Thanks again!

[LegadoOrganicDistillery]

5 hours ago, Silk City Distillers said:

A good starting point for bench trials is 5 grams a liter for darker aged spirits, 2.5g/l for lighter aged spirits.  This will give you a good idea why the holding capacity of the filtration is important.  A 500 liter batch of spirit might require 1.2kg (2.7lb) of PAC.  

I've decolorized bourbon using this method, just to screw with peoples heads by pouring them a glass of ice-clear bourbon.

Do you have any recommended suppliers?