World of Avallone - Men's Fashion & Lifestyle
Tannins - What Do Wine and Leather Have in Common? February 11 2015
One of the fascinating things about wine (aside from its uncanny ability to help ease us over annoying Dow Jones industrial average related unpleasantries) is its ability to change flavor and even texture as it sits in your glass. Especially red wine. Wine, like most foods, is a complex mixture of chemicals that change with temperature and exposure to air. But wine has a particular class of compounds, called tannins, that almost magically transform from something that can seem harsh and unyielding to something softer and far more flavorful.
The name “tannins” is actually based on tanning hides – the same compounds help turn relatively fragile animal skins into more durable materials like leather. They’re part of a group called phenolic compounds and are found in the skins of red wine grapes, in coffee, tea, chocolate, and in certain leaves and vegetables. What they share is an ability to cause astringency, which is a tactile property, a sort of dry and rough feeling in your mouth, sometimes described as “puckery,” that comes when you eat certain foods. It’s not acidity, although highly acidic foods can cause a similar sensation. Think of drinking black coffee or a freshly-opened red wine – it feels a little rough in your mouth and almost leaves you thirsty. That’s because of the tannins, which also contribute some bitterness to the flavor.
The tannins bind to the proteins in your otherwise slick saliva (we know we know – eew) , and join the proteins together to form larger molecules. These larger molecules have a rougher feel to them. They contribute to what you perceive as the substance of the wine – you may have heard some wines described as “chewy,” and that’s because the larger molecules bump into each other and slow down the movement of liquid. The tannins, combined with the alcohol and some other components in wine, help create the impression of fullness of texture. They also help keep the flavor of the wine going while you’re eating food, rather than the wine being swept out of your mouth by your meal.
So what happens to wine when it’s exposed to air? Oxygen changes the tannins into compounds that are less bitter and less astringent, essentially softening them. This allows other flavors in the wine to come through, while still making the wine seem substantial. (You can also soften tannic foods by introducing other proteins for the tannins to bind with – this is what happens when you add milk to coffee, for example, and it seems easier to swallow than black coffee). Other flavor components in wine also develop with exposure to oxygen, but softening the tannins allows some of the more subtle flavors to emerge and all the other flavors to assert themselves. Aging wines in oak also helps soften tannins, both because a small amount of oxygen gets into the barrels, and also because some of the compounds found in the wood react with the tannins.
The amount of tannin people like in wine is a matter of personal preference – and what you’re serving with the wine. So if you need another fun parlor game to add to your repertoire, begin by gathering your finest leather accessories for the complete tannin experience. (And by “leather accessories,” we mean your Avallone handmade leather bag or wallet, so get your mind out of the gutter!) Then you can try an experiment with two bottles of first vine wines, the Cave la Vinsobraise Diamant Noir and Emeraude. Both wines are 60% Grenache and 40% Syrah, and both have a fair amount of tannins, mostly from the Syrah. Open them, pour a glass of each, and taste them (with a little water and bread in between to clean the palate). The Emeraude is aged in oak and will seem less tannic than the Diamant Noir, which is aged in concrete. Then let them both sit in the glass for half an hour or so, swirling them for aeration a few times during the wait. When you taste them again, you’ll find that they both are much less tannic, and some flavors that seemed muted before are now out in front. Also, the oak now seems to affect the Emeraude differently. Some describe the Emeraude as more elegant, perhaps because the oak reduces the tannins more. (If both wines still seem too tannic to you, check out the everyday reds category for wines with softer tannins.)
Buying a New Leather Bag or Wallet? – What You Need to Know First December 22 2014
A major part of making a smart purchasing decision when buying a leather jacket, leather bag, belt, wallet, or any other leather product is knowing exactly what kind of leather it was made with, and what characteristics that type of leather embodies. Once you familiarize yourself with the different manufacturing processes involved, and the different types of finished leather used on products today, you will drastically reduce your chances of being ripped off.
For those of you who do not know, companies produce leather by transforming a raw animal skin or hide into leather through a manufacturing process called “Tanning.” Tanning basically cures the animal hide, and prevents it from further decomposition. Once leather is tanned, companies use a finishing process to finalize the desired look and feel of the leather. It is through a combination of different tanning and finishing processes that result in the many varieties of leather you currently see in stores.
Some of the most popular tanning methods today are Chrome tanning and Vegetable tanning. There are also many other tanning methods that the majority of people are not familiar with. However, for our purposes we will cover the 4 most common methods; i.e. the ones responsible for producing the leather you will most likely encounter on your next trip to the store. The following is a list of each tanning process and the type of leather that results from it:
- Vegetable-tanned leather is tanned using tannins and other ingredients found in different vegetable matter, such as tree bark prepared in bark mills, wood, leaves, fruits and roots and other similar sources. It is supple and brown in color, with the exact shade depending on the mix of chemicals and the color of the skin. This is one of most natural ways to tan leather, and it is the only form of leather suitable for use in leather carving or stamping. This leather is not stable in water; it tends to discolor, so if left to soak and then dry it will shrink and become less supple, and harder. In hot water, it will shrink drastically and partly congeal, becoming rigid and eventually brittle. However, if treated with certain finishes and dies, this water instability can be prevented. The leather can be purchased in naked form, or in different colors finished by the manufacturer.
- Chrome-tanned leather, invented in 1858, is tanned using chromium sulfate and other salts of chromium. It is more supple and pliable than vegetable-tanned leather and does not discolor or lose shape as drastically in water as vegetable-tanned. More esoteric colors are possible using chrome tanning. The chrome tanning method usually only takes a day to finish and the ease and agility of this method make it a popular choice. It is reported that chrome tanned leather is responsible for close to 80% of the leathers in the world.
- Aldehyde-tanned leather is tanned using chemical compounds of glutaraldehyde or oxazolidine. Most tanners refer to this leather as wet-white due to its pale cream or white color. It is often seen in automobiles and shoes for infants, and is the main type of “chrome-free” leather.
- Rawhide is made by scraping the animal skin thin, soaking it in lime, and then stretching it while it dries. Rawhide is not technically "leather", but is usually lumped in with the other forms. Rawhide is stiffer and more brittle than other forms of leather; it's primarily found in uses such as drum heads and parchment where it does not need to flex significantly; it is also cut up into cords for use in lacing or stitching and for making different dog toys.
Once the leather tanning process has been completed, the newly tanned leather needs to be sent through a finishing process. Remember it is a combination of the tanning process and finishing process that gives you the finished leather seen in stores. Most tanning and finishing processes can be mixed and matched. For example, you can make Vegetable tanned full grain leather, or you can make chrome tanned full grain leather. Different finishing processes result in different leathers. The following is a list of the most common finished leathers with some explanation on how they were finished.
- Full-grain leather refers to hides that have not been sanded, buffed, or snuffed (as opposed to top-grain or corrected leather) to remove imperfections (or natural marks) on the surface of the hide. The grain remains allowing the fiber strength and durability. The grain also has breathability, resulting in less moisture from prolonged contact. Rather than wearing out, it will develop a patina over time. High quality luxury leather furniture, shoes, leather briefcases, leather wallets, leather belts, and many other items are often made from full-grain leather.
- Top-grain leather has had the "split" layer separated away, making it thinner and more pliable than full-grain. Its surface has been sanded and a finish coat added to the surface which results in a colder, plastic feel with less breathability, and it will not develop a natural patina. It has greater resistance to stains than full-grain leather, so long as the finish remains unbroken.
- Corrected-grain leather is any leather that has had an artificial grain applied to its surface. The hides used to create corrected grain leather do not meet the standards for use in creating vegetable-tanned or aniline leather. The imperfections are corrected or sanded off, and an artificial grain embossed into the surface and dressed with stain or dyes. Most corrected-grain leather is used to make pigmented leather, as the solid pigment helps hide the corrections or imperfections.
- Split leather is created from the fibrous part of the hide left once the top-grain of the rawhide has been separated from the hide. During the splitting operation, the top-grain and drop split are separated. The drop split can be further split (thickness allowing) into a middle split and a flesh split. In very thick hides, the middle split can be separated into multiple layers until the thickness prevents further splitting. Split leather then has an artificial layer applied to the surface of the split and is embossed with a leather grain. Splits are also used to create suede. The strongest suede’s are usually made from grain splits (that have the grain completely removed) or from the flesh split that has been shaved to the correct thickness. Suede is "fuzzy" on both sides. Manufacturers use a variety of techniques to make suede from full-grain.
Additional Finished Leathers that are derived from the main categories seen above.
- Nappa leather is a kind of full-grain leather first made by Emanuel Manasse in 1875 whilst working for a tanning company in Napa, California. That is how the leather got its name. Nappa leather is full-grain un-split leather made from kid, lamb or sheep skin. Nappa leather is typically chrome tanned to give it a very soft and supple feel, and dyed so as to obtain various colors.
- Nubuck is top-grain cattle hide leather that has been sanded or buffed on the grain side, or outside, to give a slight nap of short protein fibers, producing a velvet-like surface
- Patent leather is leather that has been given a high-gloss finish. Patent leather usually has a plastic coating, and can be made from any type of hide.
- Vachetta leather is a type of full grain leather and is used in the trimmings of luggage and handbags. The leather is left untreated and is therefore susceptible to water and stains. Sunlight will cause the natural leather to darken in shade, called a patina.
- Belting leather is a type of full-grain leather that was originally used in driving pulley belts and other machinery. It is found on the surface of briefcases, portfolios, and wallets, and can be identified by its thick, firm feel and smooth finish.
Now that you are familiar with the main tanning and finishing processes, and the different leather those methods produce, you can put that knowledge to good use. Next time you are shopping, whether on the internet or in the store, take a look at the tag or description of the leather bag, wallet, or belt you are buying. Take note of the type of leather it was made with, think back on the processes used to produce that particular leather, and what type of characteristics those processes give that leather. You will now have a better idea on the durability and use you will get from that leather product before spending your hard earned money.