_Standardshell._—Those requiring very strong pressure of the hand or the
use of a nut-cracker to break. These may have a spongy or smooth outer
shell.
_Hardshell._—Those which cannot be broken by hand but require a sharp
blow with a hammer or strong pressure with a nut cracker to crack them.
The papershell varieties are excellent for shelling as they contain a
large percentage of kernels which may easily be obtained whole. The
principal objections are that birds are particularly fond of them since
they can crack them easily, and the shells are often poorly sealed. The
latter fact makes it difficult to prevent worm infestation and to prevent
the penetration of sulphur fumes to the kernel during the bleaching
process. As a result practically none of the papershells are bleached but
are sold for shelling purposes.
The softshells are generally more attractive for table use because the
shells are more perfect and, in commercial varieties, are brighter in
color and more attractive. The shells are usually well sealed and can
be bleached to give additional brightness with less danger of the fumes
penetrating to the kernel than the papershells.
[Illustration: Fig. 28.—Almond varieties.