Using Inert Gases in Winemaking – WMA029

Using Inert Gases in Winemaking – WMA029

http://traffic.libsyn.com/winemakersacademy/wma029.mp3Podcast: Play in new window | DownloadSubscribe: iTunes | Android | RSSJust recently I tested out Private Preserve while bottling a raisin wine. Private Preserve is an aerosol can filled with a mixture of inert gases. In this episode we’re going to explore what inert gases are, why it’s beneficial to use them, and I’ll share my own thoughts and experiences using these gases. What are inert gases? Inert gases are gases that do not normally react with anything. Unlike oxygen which oxidizes things like metal, wine, and food, inert gases do not interact with these at all. You can expose metal to an inert gas and it won’t rust so long as that is the only gas the metal is exposed to. This ties into why you would want to use inert gases when making or more accurately storing wine. Why Should I Use an Inert Gas to Protect Wine? The best use of inert gases in winemaking is to displace the oxygen in a container of finished wine. After a wine has finished fermenting it will be susceptible to the negative effects of oxidation. A wine that has been exposed to too much oxygen will taste flat, flabby, and past its prime. Inert gases are used in a process called sparging, which is a fancy term for displacing the oxygen in a container with inert gases. Generally you would have your wine in whatever container it is going to be aged in, be that a carboy or bottle, or whatever and then you spray an inert gas to remove the oxygen and quickly recap the container to trap the gasses. Now you can also sparge an empty container and then fill it with wine, same thing. The Easy Way to Try Inert Gas Private preserve is probably the easiest way to dip your toe in the use of inert gases. It comes in an aerosol can and runs about $20 US. The can contains a mixture of carbon dioxide, nitrogen, and argon and according to the manufacturer are “all benign, non-flammable, tasteless, and medial quality”. The can does come with a short straw that you can use to direct the flow of gases. Originally it was developed for wine drinkers to top up their open bottles of wine to preserve it for the next day. I’d certainly go that far if I was drinking something expensive or really fancy but it also comes in handy for home wine makers looking to try inert gases. The alternative is to go out and buy a tank of inert gas but in addition you’ll need hoses and regulators to control the flow of and direct the gas into your container of choice. Generally these gases come in decent sized tanks that might take a home wine maker a long time to go through. I’ve priced small systems out and found that it would take $150 – $200 to get going with inert gases. This is pretty expensive in comparison to $20 for the aerosol can. Using Private Preserve When you pick up a can of Private Preserve the first thing you’ll notice...

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Stopping a Wine Fermentation – WMA028

Stopping a Wine Fermentation – WMA028

http://traffic.libsyn.com/winemakersacademy/wma028.mp3Podcast: Play in new window | DownloadSubscribe: iTunes | Android | RSSStopping a Wine Fermentation Is it possible to stop a fermentation by adding sorbate or sulfites or both? This is a common question I get from wine makers. While it is possible to do it can be tough. Even commercial wineries sometimes struggle to stop it right where they want it. Home winemakers have it even tougher without the fancy equipment wineries use. In this episode of the podcast I’ll address how fermentations can be stopped as well as some common misconceptions concerning the use of sorbate and potassium metabisulfite to stop a fermentation. Questions Answered My wines keep developing mold even though I’m using sulfites. What’s going on here? I started my wine 5 days ago and now the airlock is bubbling very slowly, is it okay? Is there a way to salvage the wine at the bottom of the carboy with the sediment in it? Resources & Products Mentioned Stabilizing Wine for Back Sweetening How To Backsweeten a Wine How to Back Sweeten a Wine Kit The Difference Between Primary and Secondary Fermentation How Long do Primary and Secondary Fermentations Last? Photograph by: Tim Patterson...

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Controlling Wine Fermentation Speeds

Controlling Wine Fermentation Speeds

The speed of a fermentation is a function of many different variables. Once you understand these variables you can manipulate them to slow down or speed up a fermentation. Most wine makers agree that a slow fermentation is better. The thinking goes that the wine will hold on to more of the varietal characteristics as well as any delicate flavors and aromas created during fermentation. More aggressive fermentations tend to blow all varietal character out the airlock, so to speak. Despite the stated benefits of a slow fermentation, there may be times when you need to speed things up. For instance, if your fermentation has been slowing down and you’re affraid it may become stuck, this would be a good time to get things moving again. Another possibility is some constraint on the winemaker’s time such as a trip or something. With all of this in mind let’s explore the major factors that affect how fast wine ferments. Fermentation Temperature This is a pretty obvious driver of fermentation activity. As you know heat is a catalyst and when applied to a fermentation the yeast will ferment must more quickly. Cool the wine down and the rate of fermentation will also slow down. There are, of course, limits to how far you can go both on the warmer and cooler sides of the spectrum. Temperature is something we’ve often discussed here at Winemaker’s Academy. Here are a couple related articles: The Effects of Fermentation Temperature on Wine How to Control Your Wine Fermentation Temperature – WMA009 Raising fermentation temperatures is decidedly easier than lowering it. Kurt recently shared a great method for controling fermentation temperatures you should probably check out. To cool a wine you either need an ice bath or some sort of chiller (check out the podcast above for more information). Your best bet is to ferment your wine in a cool room (60-65 F / 15-18 C) and use a heating system as needed. Nutrient Levels Yeast nutrients is an additive which provides nitrogen and ammonium phosphate. These help the yeast stay healthy and active. Much like you and I do better when we’re getting all the right vitamins and minerals so too does yeast do better with nitrogen and ammonium phosphate. Nutrients are required for the yeast to do their job but they don’t make for a good catalyst for speeding up or slowing down a fermentation. I recommend using the amount specified in your wine making recipe, or if you’re not following a recipe 1 teaspoon of yeast nutrients (affiliate link) per gallon of must is what LD Carlson suggests. According to professional winemaker John Garlich, yeast nutrients are like candy to yeast. They focus on eating that while it’s in abundance because it’s easier to process than sugar. However, when it runs out they can have trouble switching gears into consuming sugar. Listen to this interview with John for more information Wine Making Chemistry with Bookcliff Vineyards – WMA015. I don’t recommend adding extra nutrients to speed up a fermentation nor should you reduce the nutrients to slow things down. I recommend adding an appropriate...

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Basic Wine Chemistry – WMA027

Basic Wine Chemistry – WMA027

http://traffic.libsyn.com/winemakersacademy/wma027.mp3Podcast: Play in new window | DownloadSubscribe: iTunes | Android | RSSBasic Wine Chemistry In this episode of the Winemaker’s Academy Podcast I go through the recommended values for various chemistry related aspects of wine such as: pH Titratable Acidity Alcohol Residual Sugar Sulfites For each of these I share the recommended values you can shoot for when making wine to help produce a more balanced wine. As you’ll hear in the show I don’t recommend making wine by the numbers and you certainly shouldn’t see these ranges as hard and fast rules. There may certainly be great wines with chemistry outside of these ranges but it is helpful to know where most balanced wines fall on the various scales. Aside from starting with great fruit and keeping your wine safe from spoilage getting the chemistry right is just as important to making a better bottle of wine. Questions Answered How can I lower my final specific gravity? When is wine technically start aging? Is it okay to use a sanitizer comprised of hydrogen peroxide and acetic acid? Resources & Products Mentioned Winemaker’s Answer Book by Alison Crowe Wine Alcohol Content Calculator Winemaker Magazine Measuring Residual Sugar Calculating Correct Sulfite Levels Kurt’s Temperature Control System Star San 3 Ways You Can Support the Podcast (as mentioned in the show) Become a Patreon Supporter Submit a wine making recipe Leave a review in iTunes or Stitcher Photograph by: CaptMikey9...

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Help My Wine Smells Like Bananas

Help My Wine Smells Like Bananas

There is an incredible amount of aromas one can detect in a wine. Some are fruity some aren’t. As you can well imagine some smells are okay and other signify that something has gone awry. Recently Emmett, a Winemaker’s Academy member, wrote in with the following problem: During degassing of my kit, I noticed my wine smelt like bananas. Its a Cabernet Sauvignon so needless to say, banana isn’t in that wines sent profile. Any ideas on where this may be coming from? I know that wines like Beaujolais Nouveau will sometimes have Banana like aromas, but I’ve never heard of it connected with a Caberney Sauvignon. Causes of Banana Odors in Wine It is certainly possible to pick up banana flavors from the fermentation process. As Emmet points out, Beaujolais is known to have banana aroma and flavors as a result of carbonic maceration. Other wines may also exhibit these aromas if they contain Isomyl Acetate or Ethyl Octanoate, both of which are naturally occuring biproducts of the fermentation process (read more here). As long as these chemicals are in small enough concentrations the wines will be fine to drink and the banana may even add a bit of a pleasing twist to the flavor profile. In higher concentrations, however, these wines may be undrinkable. There are two main causes of banana odors in wine outside of what can occur naturally. The first cause is cool fermentation temperatures and the second is spoilage. Let’s look at each in a little more depth. Cool Fermentation Temperatures According to Master of Wine Debra Meilburg, “Banana-like aromas appear in wine when grapes are fermented at excessively cool temperatures.” (read the entire article here) So if your fermentation dipped below the recommended temperature range for your yeast, banana aromas may ensue. As you know, when yeast digest the sugars and nutrients in a wine must they alter them. Chemical compounds in grapes called stereoisomers are taken in by the yeast where they are subjected to enzymes used to digest sugars. This interaction changes the stereoisomers and makes them take on flavor and aroma characteristics of other fruits. When yeast is under stress, such as when temperatures get too hot or cold, the yeast will produce off flavors. Just like you and I can’t do our best work if we’re not comfortable, yeast will struggle with an extreme environment. Banana odors are one example of an odor that can be produced by stressed yeast. Spoilage The other possibility is that your wine is contaminated with a spoilage micro-organism. When acetobacter contaminates a wine it converts the alcohol into acetic acid (vinegar). In the presence of 1-pentatol (a rather unpleasant form of alcohol) the acetic acid will mix with it and produce amyl acetate which smells like artificial banana flavoring. Unfortunately for our friend Emmet, this was the case. What started out as a mild banana odor gradually gave way to vinegar odors. Somehow his wine was exposed to acetobacter and, perhaps due to stress on the yeast, 1-pentanol was likely present. The two combined to give the banana odors. Over time, however, the acetobacter converted...

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