Basic recipe won’t give a black English rappee we are familiar with. It would be drier than we are used to, colour brown and lacking in alkalis.
Expressed by ingredients mass fraction (mass %), basic snuff recipe would look as follows:
Tobacco 65.7%
Water 21.7%
Salt 11.6%
Sodium carbonate 1%
Such small amount of alkali would not render pH 9-9.5, typical for a modern rappee. So, you need to dial up water and alkalizer and respectively reduce the excessive amount of salt.
My reply to the query on r/nasalsnuff (if someone else is interested in a prescription for a strong dark/black rappee) Reddit - Dive into anything.
P. S. The genuine recipe - Prescription for Hannover Snuff (kindly provided by @snuffmiller Jaap Bes) - which the aforementioned basic 101 snuff recipe was derived from by @Juxtaposer, is more intricant (although not a rappee either). It calls for even smaller amount of alkalizer (or… was it a cream of tartar or wine lees originally, @snuffmiller?) and water, yet incorporates ammonium chloride and is more balanced out on salt:
“For 500 grams of powdered tobacco, take 10 grams of fine cut yellow sweet clover, mix with 40 ml boiling water and let it to cool down. Filter the infusion and add to the filtrate 50 ml tap water, 10 grams Ammonium chloride and 5 grams Potash. Mix well with the tobacco and leave in a warm place to ferment. After convenient fermentation cool down with 50 grams of kitchen salt.”
Hannover snuff formula in mass %:
Tobacco 75%
Water 13.5% (6% for melilotus infusion + 7.5% for salmiak and potash)
Salt 7.5%
Yellow sweet clover (Melilotus officinalis) 1.6%
Ammonium chloride 1.6%
Potassium carbonate 0.8%