It stands for Low Conversion. A certain percentage of Nicotine will convert to Nornicotine during the curing and drying process. How much varies by the variety. Nornicotine can chemically convert to N.Nitrosonornicotine in the leaf while curing and aging, and more conversion also takes place in the burning process. Nitrosonornicotine is a nitrosamine and a group 1 carcinogen. Not something we want in our smoke. If you can reduce the amount of Nornicotine in tobacco, you also reduce the nitrosamine content.
Nicotine, nornicotine, anabasine and anatabine are four major alkaloids produced in tobacco. Many tobaccos have already been bred to contain little or no nornicotine. Research has show that the ability of the nicotine to convert to nornicotine has to do with a specific gene or set of genes in the tobacco plant. By selecting plants with genes which produce nicotine that doesn't easily convert to nornicotine, the nornicotine available which could potentially convert to nitrosamine is further reduced. The end result is a tobacco that is potentially far less harmful to the consumer.
To qualify as a low converter, less than 3% of the nicotine in the leaf is converted to nornicotine. Larry told me that all the Burleys grown today for the commercial tobacco companies are LC varieties. And most of the dark tobaccos grown these days are LC's. I expect we will see more and more LC types as time goes on. And I am all for it.
Sky