What is the diff. between Bourbon & Sourmash whiskey ?

Most, if not all Bourbons are sour mash whiskeys, but a sour mash whiskey may not necessarily be Bourbon.

"Sour Mash" refers to the process where the grains are mashed and that a portion of the mash is set aside to act as a starter for the next batch. It's slightly acidic due to the process (where "sour" comes from) and contributes flavors and consistency to the mash for subsequent batches. It's the brewing equivalent of sourdough bread (where a portion of the dough is saved and put into the next batch).

The sour mash method can be used for just about any style whiskey...malt, corn, rye, and others. However, to be called "Bourbon" it must be at least 51% corn, aged in unused, charred barrels, and be made and aged in the US (not just Kentucky). Jack Danel's has an extra step so it's not considered Bourbon, though it is a sour mash whiskey.

, 'bourbon' is a strange name for a type of whiskey, especially when you consider that most of the world's whiskey styles have admirably straightforward appellations. The whiskey made in Scotland by Scots is called scotch, the whiskeys made in Ireland and Canada are called Irish and Canadian respectively. Even bourbon's closest relations, Tennessee Whiskey and rye, frankly describe either their state of origin or principal ingredient, both completely logical approaches.

It is not a type or flavor of whiskey as is commonly thought. When a whiskey is sour mash, a portion of the old or "sour" mash is added to the new mash. (The old mash is also called "feed mash" because the old grains are used as an ingredient in animal feed.) The mash is the mixture of grain and hot water that the actual whiskey is made from. The sour mash process is done to improve the consistency and quality of the liquor so that every bottle tastes as close to the same as possible. The acid introduced by using the sour mash controls the growth of bacteria that could damage the whiskey. Sour mash is popular in bourbon whiskey and Tennessee whiskey. Some popular examples of sour mash whiskey are Jack Daniel's and Jim Beam.

that makes bourbon and sourmash the same both whiskey but the made differently.

It is a technical issue and is mainly that only whiskey distilled in Bourbon County Kentucky is allowed to be termed and labelled as Bourbon.

Most if not all whiskey are made from a grain, either corn, rye here in Canada, scotch is made with barley and Irish whiskey is made with a combination of grains and is either double or triple distilled.

Both sour mash and bourbon are made from corn brewed the same way, distilled and aged in charred american or french oak barrels for a minimum of 3 yrs, this adds the colour, caramel and vanilla flavours and give the mix its character.

But as I said bourbon is only made in Kentucky along the river that runs through the county with the name Bourbon, check out some of makers websites for more details.

I am a veteran Jack Daniels and Makers Mark drinker and they are 2 very different tastes and experiences.

They are essentially the same. However, while bourbon is distilled in a very specific way (and in very specific locations), it may or may not contain sour mash. Also, while bourbon is made primarily from corn, other adjuncts (grains) may be added as well, such as wheat or rye.

Sour mash refers to bourbon, and other whiskeys as well, which have been distilled from corn; part of the fermented corn "wert" (the pre-distilled product) is siphoned off, and later added to fresh batches. This is done to ensure that all batches of the whiskey have the same characteristics. It is quite literally the same procedure as used in sourdough breads: part of the fermented "sponge" is carried over into subsequent batches.

They're the same thing.