Whole Leaf Tobacco - Tobacco Problems (2024)

If the relative humidity (shownas percent in the chart) is kept below 76%, the risk of mold growth is quitelow. As the humidity is increases above that (in typical home temperatures),the risk increases dramatically. Tobacco that is damp will usually notmold over a span of a few days, but after that may suddenly bloom with commonmolds. Since mold spores are ubiquitous, their control is generally limited tomanipulating the humidity, in order to inhibit them (in the absence of chemicalanti-fungal agents).

Mold typically appears on the thicker parts of the stem first, since this region of whole leaf is mostlikely to hold the most moisture, and release it slower than the leaf lamina.In stemming a leaf for use, if there is slight mold only on the stem, then itcan be ignored once the stem is discarded.

b. Mold concerns
Mold on the laminacreates two issues. The most obvious is its impact on the smell of thetobacco. If it smells moldy, it will be unpleasant to smoke or use in asmokeless preparation.

A more important issuewith mold is its potential to create toxins within the tobacco on which itgrows. Of greatest concern is aflatoxin (commonly produced by species of Aspergillus,which may be white, black, gray or yellow). Aflatoxins can permanently damagehuman tissues, including the liver—and can cause liver failure.

When aflatoxin is burned,during the combustion of tobacco, no toxin is detectable in the smoke. Bycontrast, aflatoxins that are in non-burned tobacco (e.g. snus, snuff, chew,and the wrapper of a cigar in the mouth) are absorbed into the tissues of themouth and nasopharynx.

So if there is any concern about using tobacco that might be moldy, its use in cigar filleror a cigarette or in pipe tobacco is probably safe. Such tobacco should not beused in smokeless products or as a cigar wrapper.

c. Control of mold
Very slight mold can meinhibited by misting the tobacco lightly with diluted (50:50) hydrogenperoxide. But by far the wisest policy is to prevent mold in the first place,by controlling the ambient humidity.

With regard tocontrolling humidity, one factor that is often ignored is storage of a closedcontainer of tobacco in ambient temperatures that swing back and forth. If,for example, a sealed bag of tobacco is exposed to a 20°F increase intemperature, the internal relative humidity drops by half. If the ambient tempdecreases by 20°F, then internal humidity will likewise rise.

That in itself is not amajor issue under most circ*mstances. But a container of tobacco exposed toswinging temperatures does not alter its internal temperature uniformly—someparts of the contents becoming warmer than other parts of the contents. Thiscauses a heat pump effect, by driving moisture from the warmer areas,and then condensing that excess moisture within the cooler areas. The resultof this heat pump effect caused by swinging ambient temperatures is to createfavorable conditions for mold growth in portions of the contained tobacco. Theeasiest way to avoid this is to store tobacco containers (bags, tubs, etc.) inliving areas of a home that are the most stable with respect to ambienttemperature. In large tobacco containers (5 to 10 pounds), periodicallyinspect the tobacco withing the most interior regions.

Whole leaf shipped by WLTusually comes in sealed bags. Their poly-nylon bags are entirely vapor-proof,and their heavy gauge polyethylene bags are nearly so. It is sealed within thebags at medium case (fully pliable, but not damp) at controlled, warehousetemperature—like a typical home. If the sealed bag is shipped or stored at asignificantly lower temperature, the internal relative humidity will increase.

These shipping bagsshould be carefully opened with scissors, cutting a clean line across the sealat the top, so that the top edge can subsequently rolled, flattened andclamped, to retain humidity. Each time the bag is opened, for inspection, orto remove some leaf, the humidity of its contents drifts toward that of theroom environment in which it is opened. If the ambient environment tends to bemore humid, then the leaf’s moisture content may increase toward it. If theambient environment tends to be drier, then the leaf will gradually dry.

If the leaf in acontainer becomes too moist (risking mold), that can be reduced by gentlywarming the open bag, to drive off some of the excess moisture, thensealing the bag again. If the leaf is too dry, its contents can be lightlymisted with non-chlorinated water, then sealed again. Light misting willdisperse its humidity into all the leaf in the bag over a period of a few hoursto a day.

Lasioderma serricorne, the tobacco beetle, first became apest of cured tobacco over a century ago. It initially was a problem intobacco warehoused in the Philippines as well as other areas of the Far East. Butsubsequent world trade, coupled with poor pest control measures, led to itsspread throughout the world. It is now a ubiquitous pest.

The tobacco beetle is abrown, pinhead-size (2-3mm) beetle that can fly. It is its larval forms thatlike to tunnel through cured, finished tobacco leaf—both lamina andstems—leaving easily identifiable holes as well as "dust". Tobacco warehouseseverywhere today regularly inspect for it, and fumigate their tobacco toeliminate it. But it nonetheless persists. The adult beetles can besuccessfully wiped out, but then return when its eggs hatch and mature.

Lasioderma serricorne can hitcha ride into a house in any tobacco or tobacco product (including commercialcigarettes), as well as in purchased, dried grains and cereals (includingbreakfast cereals), flour, commercial bread crumbs, and a host of other items.If they get into a cigar humidor, they may tunnel through wrappers on expensivecigars, and otherwise create damage to tobacco, and to foods in the pantry.

Once tobacco beetles havebeen detected within a home (in a humidor or pack of cigarettes, or in storedtobacco or pantry foods), they are quite difficult to eliminate. The beetleand its eggs can be killed in stored tobacco by placing the closed bag in thefreezer and leaving it there for a week to 10 days. (The adults die within 6days at 4 °C [39.2° F], and eggs survive 5 days at 0–5 °C [32°F].) Individualbags, cartons or boxes of pantry foods can be kept within closed Ziploc bags,and tossed if seen to be infested.