Whisky main material is grain. Starch in grain is converted to alcohol via sugar during making process.
It's germinated dried barley. Malt whisky uses only malt without any other grains but almost all grain whisky contain malt in mash together with other grains because only malt has enzymes for converting starch in grain to sugar.
Malt is dried and removed root just after germination to stop further growing up. Some malt is dried by peat and it makes peat flavor whisky.
There are 2 type barley, 2-raw and 6-raw. 2-raw barley Malt has good balance of starch and enzyme for malt whisky. 6-raw barely Malt has more enzyme than starch. It can covert not only starch in Malt but also starch in other grains to sugar. It is used for grain whisky sometime.
Rye malt is also used rarely for rye malt whisky.
Normally barley is converted to malt to use for whisky but Single pot still whiskey in Ireland uses non-malted barley partially together with malt in same mash (and other grain like oat rye and wheat traditionally)
American/Canadian rye whisky is made from mash which is more than 51% rye.
Canadian whisky is called rye whisky sometime but except for Canadian rye whisky, it is actually blended whisky of corn-main base whisky(Around 90%) and rye-main flavoring whisky(Around 10%).
American corn whisky is made from mash which is more than 80% corn. Bourbon require 51% instead of 80%.
Corn main mash enable sweat flavor and taste whisky.
But corn starch is hard structure so that some distillery boil milled corn before mashing
American wheat whisky is made from mash which is more than 51% wheat.
Due to loose PDO regulation in Japan, some spirits made from rice and malt aged in cask are sold as "Japanese rice whisky".
There are also a few barley and malt whisky in Japan.
In Addition of above, Oat is used for whisky traditionally. But some of new craft distilleries are challenging several grains like Farro, Foxtail millet, Buckwheat and Quinoa recently.
Milled Malt(Grist) Size
Milled malt is called "grist" Malt is milled to 3 different size before mashing.
Hask filters flower which cause clogging in mash tun.
It's main enzyme material for mashing
It cause clogging in mash tun. But grist always contain some flower and it is filtered by hask.
Whisky Enzyme & Yeast
Enzyme convert starch in grain to sugar which is converted to alcohol by yeast in next step.
Almost all whisky use enzyme in Malt for mashing except for rice whisky by koji.
2-raw barley Malt
2-raw barley Malt has good balance of enzyme and starch to make Malt whisky.
6-raw barely Malt
6-raw barley Malt has good more enzyme than starch. It is used for grain whisky mash because it has enough enzyme to convert starch not only in Malt but also in other grains to sugar.
Rye malt is used rarely for rye malt whisky in USA.
Koji is compound of koji mold and base grain.
There are several different type koji by base grain (Rice, Barely, Sweet potato and Soy bean) and koji mold type (White, Black and Yellow)
Normally Rice-Yellow koji is used for sake, White koji(Several different grain) is used for Shochu. Black koji(Several different grain) was originally used for Awamori but it is also used for Shochu today.
Some rice whisky uses koji instead of malt. It doesn't contain
Yeast is essential to convert sugar to alcohol after malt enzyme converting starch to sugar.
Majority of Scotch distilleries think Yeast doesn't have influence of whisky flavor and taste today.
However American and Japanese distilleries have opposite idea.
There are hundreds whisky yeast but most popular is distillery yeast which was developed in 1950s.
It is very good fermentation capability with good flavor.
Many distilleries are using brewery yeast provided from Ale beer brewery together with distillery yeast.
It provides rich floral/fruity flavor (Ester).
Some distilleries are challenging other yeast like champagne, sake and etc.
Whisky material category
Whisky material common category in the world
Whiskeys around the world can be broadly divided into malt whiskeys made only from malt and grain whiskeys made from malt and other cereals. Blended whisky normally means blended of malt whisky and grain whisky.
Malt whisky in almost all countries without America uses only malt which is germinated barley without any other grains.
Normally malt for malt whisky is made from tow-row barley because it has good balance of starch and enzyme.
Major malt whisky is Scotch Malt, Irish Malt and Japanese Malt. Malt whisky containing more than 2 different countries malt whiskies are sometime labeled as "Pure Malt" or "World Malt"
American malt whisky is actually grain whisky due to required material by unique USA regulation.
Grain whisky uses both malt and other grains like corn, rye, wheat, oat, non-malt barley and etc. Malt is essential even for grain whisky because other grains doesn't have enzyme to convert starch to sugar.
Malt for grain whisky is made from six-row barley in stead of tow-row barley because it has much more enzyme to convert starch in not only malt but also in other grains to sugar.
Major grain whisky is Scotch grain, Irish grain, Irish single pot still, Bourbon, American corn/rye/malt/wheat whisky. Some of them have minimum limit of specific material in mash.
Unique material whisky in Japan
Japanese distilleries started to produce following 2 type spirits and promoted as "whisky". It is not defined by any law/regulation today therefor these are actually spirits aged in oak barrel.
It is rice main grain whisky mashed by malt enzyme. It is mainly exported to US today.
Most of rice whisky are produced by Shochu distilleries in Kumamoto prefecture. They are using stainless pot still which is also used for rice Shochu (Japanese traditional spirits).
Koji Whisky (Barley/Rice)
Actually it is Japanese traditional spirits, Shochu. But Shochu has coloring degree limitation by Japanese liquor tax law so that
long aging in cask or Oke (traditional Japanese wooden container) causes over coloring degree.
One companies is promoting over colored Shuchu as Koji whisky but actually it is not whisky but liquor because mashing is done by koji instead of malt. Almost all countries requires mashing by malt for whisky today.
In 19th century, Mr. Jokichi Takahashi established this method and patented in USA.
Irish whisky material category in Ireland
Irish whisky material category is malt whisky, grain whisky and pure pot still whisky. Irish blended whisky blended of all three or two of them.
Pure pot still whisky
It is non-malted barley and malt main grain whisky in Ireland. Originally it contains not only non-malted barley, malt but also oat, wheat, rye.
Today, Irish law require min 30% non-malted barley, min 30% malt and max 5% other grains for pure pot still whisky.
American whisky material category
Almost all American whisky is grain whisky. If a specific material accounts for more than 51% of mash, whisky is called specific name whisky. Whisky with more than 2 years aging is called "Straight whisky" except for corn whisky.
It is corn main grain whisky. Min 51% alcohol should be made from corn.
Tennessee whisky has same material requirement with Bourbon and different is only one additional production process, which is filtration with charcoal made from sugar maple tree.
American corn whisky
It is corn main grain whisky. Min 80% alcohol should be made from corn.
Corn whisky aging is normally very short like half year and cask inside is not burned. Therefor most of corn whisky looks white spirits.
American rye whisky
It is corn main grain whisky. Min 51% alcohol should be made from rye.
American rye malt whisky
It is corn main grain whisky. Min 51% alcohol should be made from rye malt.
American malt whisky
It is corn main grain whisky. Min 51% alcohol should be made from malt.
American wheat whisky
It is corn main grain whisky. Min 51% alcohol should be made from wheat.
Canadian whisky material category
Most of Canadian whisky is blended of flavoring whisky and base whisky with Max 9.09% flavoring liquor.
Canadian whisky is called rye whisky however flavoring whisky is only 10-15% of blended whisky.
Canadian flavoring whisky
Flavoring whisky accounts for 10-15% of Canadian blended whisky. It is normally rye main but no specific minimum requirement.
Canadian base whisky
Base whisky accounts for 85-90% of Canadian blended whisky. It is normally corn main but no specific minimum requirement.