Acid Blends in Wine Making

Acid Blends in Wine Making

What Is An Acid Blend? Acid blends are mixtures of acids that are naturally found in wine making grapes. Most blends primarily contain malic, citric, and tartaric acids. Wine making grapes contain more than just these acids but these are the three most abundant acids. Malic acid contributes tartness to wines. It is the primary acid found in apples for a point of reference. Citric acid, of course, is the dominant acid found in citris fruits. Tartaric acid also brings tartness to wine and is the dominant acid in cranberries. An acid blend is used to increase the titratable acidity of a wine. While the point here is to adjust the amount of acids contained within the must it will have an affect on the pH of the must, a measure of the strength of the acids present. Grape acids are usually at the following concentrations: Tartaric = +6 g/L (50%) Malic Acid = 4-6.5 g/L (40%) Citric Acid = 0.1-0.7 g/L (10%) LD Carlson acid blend comprised of the following: Tartaric Acid = 10% Malic Acid = 50% Citric Acid = 40% As you can see the ratio of acids in the acid blend is not the same as you see in wine making grapes. This means that a wine must treated with an acid blend could have an unnatural mixture of acids. While this isn’t necessarily a bad thing from a taste perspective some wine makers feel like this can lead to balance issues. Wine makers that choose not to use acid blends will often add acids individually depending upon what they’re trying to accomplish. For instance tartaric acid can be added alone to increase tartness and increase titratable acidity to a more palatable level while avoiding the addition of too much citric acid. You should also know that different brands of acid blends contain different ratios of acids. If the balance of each individually is something you’re concerned about be sure to ask your supplier. When To Use It Acidity is the determining factor of tartness in wine. pH is important to for understanding how strong your acids are but acidity is a measurement of how much total acid you have. So if your wine has very little acid, even if it is a strong acid, the wine will not have a tart component to it. This can lead to flabby wines. Acid blends should be used to treat the must prior to fermentation. Getting the balance correct not only makes your wine taste better but also helps the yeast do their job better. Some fruit wine and mead makers will add acid blends just prior to bottling. They measure the amount by taste and not with a scale. This practice is largely discouraged though as it can lead to a grainy mouthfeel and a less integrated final product. How Much To Use Before adding any acid blend to your wine, unless you’re following a recipe ingredient for ingredient, you need to understand what your must acidity is before adjusting it. The simplest and least expensive way to figure this out is by using a titratable...

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Adding Potassium Metabisulfite to Wine

Adding Potassium Metabisulfite to Wine

Potassium metabisulfite is a necessary preservative in wine making. It provides sulfur dioxide which helps prevent microbial spoilage and fight of oxygenation. However, figuring out how much to add can be complicated. By the end of this article you’ll understand how this stuff works, how to calculate what you need to add, and what equipment you need to do it. Let’s get to it. Why Adding Potassium Metabisulfite is Complicated With most wine additives you just measure out a specific amount to treat whatever volume of wine you have on hand. Not so with sulfites additives like potassium metabisulfite and campden tablets. The first thing to understand about sulfites is that they bind with other things in your wine. They bind with micro-organisms, oxygen, solids, yeast, acids, bacteria, and sugars. When this chemical bond happens the sulfite goes from being free to bound. Bound sulfite has already done its job and while it is still in your wine it is not free to bind with anything else. Thus we have to different sulfite levels to worry about, free and total. Free sulfites are unbound sulfer dioxide molecules that are available to bind with the bad guys to keep your wine safe. Total sulfites is a measurement of free sulfites and sulfites that have already chemically bonded with something in your wine. As winemakers we want to know that our wine is protected against the many things that can spoil it. Protection comes only from free sulfites. Thus we need to know how much we have in our wine already that is free and how much free sulfites we would like to have. When adding sulfites to wine, usually in the form of potassium metabisulfite, some of it will become bound while the rest will remain free. You can’t predict how much will become bound so you’ve got to add potassium metabisulfite, test it, then adjust as necessary. If that wasn’t enough variables here’s another twist. The effectiveness of sulfites change with the pH of the wine. The higher the pH the more sulfites you’ll need to do the same job as you would in a wine with a lower pH. Don’t worry though there’s any easy way to figure out what your ideal range is. The Effects of Time Over time the free sulfur dioxide will bind with things in your wine or it can also leave as a gas. Thus you’ll need to monitor your sulfite levels throughout the wine making and aging process. With each racking and addition of additives you’ll be using up free sulfites. These become bound and are not affected at protecting your wine. So don’t think that if you’ve added it once in the beginning that you’re good to go, you’ll likely have to add more. As you can see there are many variables we have to deal with when figuring out how much potassium metabisulfite we need to add to our wines. Now that we understand how sulfites work and where they go let’s take a look at how to calculate the right amount of potassium metabisulfite to add to your wine. How...

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How to Use Bentonite to Clarify Wine

How to Use Bentonite to Clarify Wine

Bentonite is a common additive used to clarify and fine wines. It’s great for removing protein haze and can be used to remove off aromas. But what is it? How does it work? Let’s find out. What is Bentonite? Bentonite is an impure clay formed by the weathering of volcanic ash. It is an absorbent material that is able to bond with the floating particles that cause cloudiness in wine. The main types used to fine wine are sodium and calcium bentonite. While each will contain small amounts of other minerals they are described by the mineral that is in greatest concentration. Calcium Vs Sodium Bentonite Either form may be used to clarify a wine, however, the difference between the two are the minerals that get left behind. Sodium bentonite, as the name implies, has sodium (salt) in it. After adding it to a wine it will clear what it can clear and settle out. What’s left over may be removed through racking, however, the sodium does get left behind. For commercial wineries the addition of sodium metabisulfite and sodium bicarbonate is legally prohibited by the US Tax and Trade Bureau. So while sodium bentonite is allowed it does seem that avoiding anything that adds sodium to wine is a good practice. Calcium bentonite will leave behind, you guessed it, calcium. From a wine making perspective this is much preferred over salt. However, you can go too far with this and wind up with tartrate instabilities if you add too much. Tartrate instabilities can lead to the formation of tartrate crystals. I’m sure you’ve seen these in a commercial wine before. They’re small crystals that look like a very coarse table salt. While they are harmless most consumers don’t like finding things in their wine bottle or glass. For more information on calcium vs sodium bentonite please refer to Fining with Bentonite by Christian Butzke of Purdue University (scroll down to page 3). How to Use Bentonite Bentonite is a fairly dense material and if it is not prepared correctly it will just collect at the bottom of your carboy and do nothing to clarify your wine. Here is the proper proceedure for hydrating and adding bentonite to your wine. Re-hydrate the bentonite powder by vigorously mixing 2 teaspoons with 1/2 cup water at 140 degrees F / 60 degrees C. The powder will have a tendency to clump together as it absorbs the warm water. Break up as many clumps as you can. This mixture is now referred to as a slurry. Store the bentonite slurry in a sanitized and airtight container for at least four hours. This allows the bentonite to become fully hydrated. The maximum amount of time you let bentonite hydrate is debated. Some sources say hydrate for at least 24 hours some say 48 hours. Other resources say don’t let it sit for more than 24 hours. I found 24 hours worked just fine. Add the slurry to your wine at a rate of 1 – 2 tablespoons per gallon of wine. Use one tablespoon per gallon for mild cloudiness and two per gallon for wines with a thicker...

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Using Potassium Sorbate When Making Wine

Using Potassium Sorbate When Making Wine

Potassium sorbate (or k-sorbate) is a common additive used in wine kits. It’s usually added in the form of a power after fermentation has completed. But what does it do? What precautions should winemakers be taking when using it? What does Potassium Sorbate do? Simply put potassium sorbate is used to prevent spoilage by yeasts and molds in a finished wine. It does this by rendering these micro-organisms unable to reproduce. It is added to wines that have completed fermentation to prevent spoilage but also to prevent further fermentation of sugars added after fermentation such as when you back sweeten a wine. In the case of wine kits you would add potassium sorbate prior to adding the “f-pack” (grape juice concentrate). Usually you wouldn’t add potassium sorbate to a dry red wine because the sugars have been completely exhausted and the additive is not needed. Potassium sorbate should always be used at the same time with potassium metabisulfite. Together they make for a rather inhospitable place for micro organisms. The sulfites from potassium metabisulfite removes the oxygen from your wine to prevent micro-organisms from getting established while sorbic acid from potassium sorbate renders yeasts and molds unable to reproduce. Limitations of Potassium Sorbate While this additive does stabilize wines it does have three distinct limitations. First, it is ineffective against bacteria. If stray bacteria or lactic acid bacteria were to get in your wine while using only potassium sorbate it would not prevent spoilage or malolactic fermentation (as caused by lactic acid bacteria). The combination of sulfites and sorbate help reduce your risks of this as mentioned before. The second limitation of potassium sorbate is the length of time it is effective. Once added to wine it stays in the desireable form of sorbic acid only for a short time. Over time it breaks down into ethyl sorbate which can add notes of pineapple or celery to your wine. The change into ethyl sorbate is not preventable. By using potassium sorbate winemakers are putting a definite shelf life on their wines before they pick up these off flavors. The third limitation is that it reacts poorly with lactic acid bacteria. According to my research it can produce strong geranium odors which most wine drinkers consider a flaw. Because of these limitations many wineries do not use potassium sorbate. They opt to stabilize with sulfites only an rely on their ability to properly sanitize everything to prevent spoilage. Interestingly, wines with potassium sorbate may not be classified as organic. Precautions When Using Potassium Sorbate (Please Read This!) Despite these limitations kit manufacturers include potassium sorbate in their wine making kits. This is to make sure the wine is as stable as possible even if there were some equipment sanitation lapses. Potassium sorbate should be stored in a dry area away from heat and light. Storage temperatures should not exceed 100 degrees (F). Like many additives potassium sorbate is an eye irritant. Should you get any in your eyes flush them with water for 15 minutes and get medical attention. Lastly, and most importantly, paper or cloths that have absorbed potassium...

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Using Potassium Metabisulfite to Make Wine

Using Potassium Metabisulfite to Make Wine

Potassium metabisulfite comes with just about every wine kit and is used as an additive even in wineries. This article explores what potassium metabisulfite is and how it works. To learn how to figure out how much to add to your wine check out Adding Potassium Metabisulfite to Wine (includes a calculator). But what does it do? What is it for? Is it safe? Let’s find out. What is Potassium Metabisulfite? Simply put it’s an antioxidant. It slows down the aging, i.e. oxidation, of wine by removing free oxygen suspended in the wine. Oxygen is both harmful and beneficial to wine. It is harmful in large quantities because it rapidly accelerates the aging process. However, wine starved of all oxygen can develop off flavors. The solution? Remove all oxygen suspended in the wine, bottle it, and let tiny amounts back in through natural cork closures. This is what we call micro-oxygenation. Potassium metabisulfite is often called a stabilizer because it serves to prevent spoilage and further fermentation by removing oxygen. However, this serves another purpose it preserves the flavor and color of a wine. An over oxidized wine can taste cooked or flabby (lacking body). Additionally, an oxidized wine turns red wines orange and eventually brown. White wines turn a golden brown color. This additive is available in a powdered form as pictured here as well as in tablets called campden tablets (affiliate links). Potassium metabisulfite may also be used as a sanitizing agent due to its antioxidant properties. How Does it Work? When you dissolve PM (K2S2O5) in water it forms three different compounds, sulfur dioxide, bisulfite, and sulfite. Each of these is able to bond with free oxygen floating around in wine. When this happens the free oxygen is no longer available to be consumed by micro-organisms. The removal of oxygen chokes off most micro-organisms and will prevent them from reproducing. It does not, however, stop a fermentation. Yeast produces alcohol only when forced to live without oxygen but it does go on living. Read this post for more information on the how yeast is used to make wine. By adding potassium metabisulfite after you’ve stopped fermentation completely you can then back sweeten a wine with little risk of rekindling the fermentation of newly added sugar. A Common Misconception Sodium Metabisulfite can be used interchangeably with potassium metabisulfite. While they both have very similar chemical makeups the difference is that potassium metabisulfite leaves potassium behind and sodium metabisulfite leaves sodium behind. Potassium occurs naturally in grapes and is essential to their growth. So adding a bit more potassium to the mix isn’t going to hurt anything. There’s already some in your wine. Sodium on the other hand is not something we want to add to our wine. Can you see yourself pouring table salt into a glass of wine? No. Don’t use sodium metabisulfite. Things to Be Careful of When Using Potassium Metabisulfite There are a few things you should know about potassium metabisulfite before you use it again. First, the compounds it creates can be hazardous to your health in large quantities. SO2 is a toxic gas to breath. It can cause breathing difficulties, swelling, rashes,...

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