99% alcohol?
That sounds like "Isopropyl alcohol" was used for this extraction, as "ethanol" has a max % of
95.6% ABV.
You can also get wsomething called "absolute ethanol" which is 99-100% AVB.
Some procedures that are sensitive to the presence of water require absolute ethanol.
A common method to produce ethanol with a higher concentration than 95% is to use additives that disrupt the azeotrope composition and allow further distillation.
For this reason, absolute ethanol contains trace amounts of these additives (such as benzene).
I really don't expect anyone to even get hold of "absolute ethanol" and you wouldn't want to use it, with the additives it has in it.
Which is why when I saw 99% I instantly thought it sounded like "isopropyl" which is consistently sold at a max of 99-99.9% ABV.
Isopropyl is mildly toxic and shouldn't be used for "tinctures" (a medicine made by dissolving a drug in alcohol) as it will turn to acetone in the liver.
Even when making Qwiso (quick wash iso extraction) the isopropyl needs to be completely evaporated off before consuming.
Low concentrations of residual "isopropanol" can cause gastric disturbances, while higher concentrations can be lethal.
It is always best to use "food grade" ethyl/ethanol for extractions and tinctures.
Never ever use "denatured alcohol" which is designed to be toxic and unsuitable for human consumption.
In the USA Everclear or 151 rum can be used.
In the UK "food grade ethanol" can be bought on ebay @ around £30 a liter (just make sure you search for "food grade"!!!
OK safety bit over.
Now to to the matter at hand -
how to reduce the amount of chlorophyll in a "tincture" or "qwet" (quick wash ethanol extraction).
Solvents fall into one of two categories
"polar" or
"non-polar".
Non-polar solvents, like propane and butane, dissolve the non-polar compounds like
lipids,
oils, and
waxes comprising the trichome heads.
Polar solvents, like ethanol extract polar compounds. Water insoluble molecules, like
chlorophyll a and
chlorophyll b,are naturally soluble in alcohols like ethanol.
Ethanol is both "polar" and "non polar" so it extracts both oil soluble and water soluble compounds.
However there is a way we can reduce the "polar" (water soluble) element of "ethanol".
At warmer temps "ethanol" will extract more of the "polar soluble" compounds.
Conversely, at colder temps "ethanol" will extract more of the "non polar" compounds.
So the trick would be to chill you weed and "ethanol" before you start the "qwet" extraction process.
This will significantly reduce chlorophyll in you tincture but not completely remove it.
However a hint of "arse" is still better than, the full on taste of "arse"!
Further safety note - "alcohol tinctures" should not be given to recovering alcoholics.