Here are a few definitions of Bloom:
"Bloom, also called plume, is a grey/white residual powder that is
left from the cigar's essential oils drying on its surface, and is
considered a very good sign that the proper aging is taking place. Not
all cigars develop bloom, but those that are heavy in oils almost
always do over time."
"Bloom (often called plume) refers to the slow rising of essential
oils to the surface of the cigar. It first appears on the surface of
the cigar as tiny crystals and will eventually make the cigar appear
dusty. A more advance bloom gives an opaque white look to the entire
cigar. Bloom is not harmful to cigars. It is an indication that the
cigar has been maintained at a 70+% RH for a long period of time. Many
smokers prefer a cigar in the bloom state."
"The tiny dots which may appear after a time, are called bloom. A
certain amount of bloom is a sign of proper aging. Brush it off and
enjoy your cigar."
All the references indicate that bloom does not affect the quality of
the cigar. It appears to be a good sign that proper aging is taking
place. However, you should be aware of the difference between bloom
"The difference between bloom and mold is that bloom is the oleoresins
from the cigar coming to the surface of the cigar. This is in fact a
good sign that the cigar has a lot of taste. Mold is more spotty and
ruins the taste of a cigar. How can you tell the difference? If the
cigar comes with the spots it might be either. If it developes when
you have it in your humidor for less than a few months, it's mold. If
it's blue, it's mold. If you can brush it off, it's probably bloom."
"Mold is a fungus. It appears on the surface of cigars when the
relative humidity in your humidor exceeds 80%. It manifests itself in
blue/gray fuzzy patches on the surface of the wrapper and will spread
by producing spores. If mold appears, you should remove the affected
cigars and check for any mold on the wood of your humidor. It is
important to separate the affected cigars immediately and to wipe down
the interior lining of your humidor with isopropyl alcohol. This will
kill old and may leave slight stains on your humidor's interior wood."
A photographic comparison between mold and bloom can be found at the
following web site:
General Cigar Storage Guidance
"The most important thing to know about storing your cigars, is that
they must be store at 65 to 70 degrees of humidity and at a
temperature of approximately 70 degrees fahrenheit. Just remember the
70/ 70 rule."
RH ? Relative Humidity
I hope the above information proves to be helpful. If you have a
question or require clarification please do not hesitate to ask.