Nobody saw it coming, but Ugg Boots have certainly taken the world by storm and become a huge fashion craze. Everybody whose anyone is wearing them! Austrailians know that Ugg means "ugly" but these woolly sensations are still everywhere. Wondering exactly how Ugg Boots are made and just what makes them so comfortable? Some folks wonder if any animals are harmed during the making of Ugg Boots. The short answer is, the sheep is slaughtered. BUT, that sheep was going to be slaughtered for meat to feed people-it is never actually slaughtered to obtain the sheepskin. Sheep farmers obtain a secondary profit for selling the hides in addition to the meat. So, understand that the making of UGG Boots 5218 doesn't directly harm the sheep. Sheepskins have to be preserved properly before they can be processed into boots. Tanneries use large vessels called paddles, that hold anywhere from 3,000 to 15,000 liters of salt water and slowly swish the skins around inside. This is a gentle process that takes about 10 days to get the hides properly tanned and ready to be cut for Ugg Boots. Pickling" of the sheepskin then takes about 16 hours. Before the sheepskin can be tanned, they have to be ) pickled. Pickling means soaking the skins in a solution of acid and salt. Adding salt prevents any potential swelling of the skins because of the acid. It's important to lower the internal pH of the skins to somewhere between 2.8-3.0, which will allow the tanning agent to properly penetrate the skin. The 16-hour "Tanning" step involves using chromium salts which form cross-links with the collagen, thereby helping to stabilize the skin structure and preventing putrefaction or rotting. This step is performed at room temperature, around 25 degrees Celsius, and around a pH of 2.5-3.0. Once the tanning agent (the chromium) penetrates the skin, the process is stopped, and the chrome is fixed to the collagen by raisng the pH to 3.6 using sodium bicarbonate and heating the skins to between 35-40 degrees Celsius. In doing so, the shrinkage temperature of the skin is raised to anywhere between 60-100 degrees Celsius. Next comes "Wool Dyeing" or "Fatliquoring." This takes anywhere from 3-4 hours to complete. After the skin is tanned, the wool may be dyed any of a variety of colors. Wool dyeing needs to be done at about pH 4.5-6 and at 60-65 degrees Celsius. Special "pelt reserve agents" must be added to keep the wool dye from staining the pelt. Once the dye is stable, the pH is lowered to about 4.0 to fix the dyes to the wool, and fatliquor (emulsified oil) is added to the solution. Fatliquors are part of leather manufacturing that help to lubricate the collagen fiber and allow them to move flexibly and freely once the skin is dried. This is what makes the leather feel soft.