Specific Gravity Temperature Correction Calculator

- Jun 23, 2013

Specific Gravity Temperature Correction Calculator

All hydrometers are calibrated to be accurate at a given temperature. Most newer hydrometers are calibrated for 68 degrees (F). Because the density of fluids changes as their temperature changes if you don’t measure your specific gravity at your hydrometers calibration temperature you’re going to get an inaccurate reading. While the correction may be small for a single reading if you don’t correct it it becomes increasingly difficult to compare readings over time. For instance, if you take an original specific gravity reading at 75 degrees (F) and a final reading at 65 degrees (F) you can’t compare these readings because the fluid densities are different at the different temperatures. You must correct each of your readings for temperature differences before you can compare them. Specific Gravity Temperature Correction Calculator This calculator makes temperature corrections easy to figure out. Be sure to check and see what your hydrometer is calibrated for, while most hydrometers are calibrated to be accurate at 68 degrees (F) / 20 degrees (C) not all of them are. Inputs Specific Gravity Measured Temperature of Your Sample (F or C) Hydrometer Calibration Temperature (F or C) Temperature scale Results Temperature Correction: Temperature Corrected Specific Gravity: The calibration temperature for your hydrometer should be printed on the scale. If it’s not printed there you can calibrate it yourself by putting your hydrometer in water samples at difference temperatures and seeing when it reads 1.000. That will be your calibration temperature. The formulas used to make the temperature corrections are based on water density data presented in the Handbook of Chemistry and Physics 53rd Edition...

read more

Wine Alcohol Content Calculator

- Jun 19, 2013

Wine Alcohol Content Calculator

Calculating the alcohol content of a wine that you made is always fun. While amateur wine makers don’t need to report this value to anyone it’s just neat to know how much alcohol you’ve produced.   Use Wine Equations and Calculators Only There are many formulas out there for calculating the percent alcohol of wine and beer. You may have noticed that they’re not the same. Largely this is because the relationship between the specific gravity and the amount of alcohol produced is not linear. What this means is that specific gravity and alcohol content have a complex relationship that is not easily represented with a simple equation. Non-linear equations can be pretty nasty to deal with. To get around these nasty but accurate equations simpler equations have been developed but they are only relevant for a small range of alcohol content. Wine, typically has an alcohol content of around 11-15% while beer is usually around 5-6%. Because of this they each have their own alcohol content equation based on these different ranges of alcohol. In short be sure that you’re using an equation specific to wine making. A beer equation can lead to incorrect results.   The Wine Alcohol Content Calculator The simplest way to calculate your alcohol content is with a calculator. You’ll need to know your starting or original specific gravity that you took before fermentation began. Also, you’ll need the final specific gravity taken once your wine has finished fermenting and is stable. Just plug in both values and press calculate.   Original Specific Gravity: Final Specific Gravity: % Alcohol by Volume:   This is about as accurate as you can get with the equipment and methods available to amateur wine makers. Wineries use distilling equipment as shown above to get a more exact alcohol content. To ensure that you get as accurate a result as you can you need to take accurate specific gravity readings. Also, be sure to do your temperature corrections for the greatest accuracy. Check out this article and calculator for correcting your specific gravity readings for temperature.   The Equation for Calculating Alcohol Content For those of you who’d like to know the equation behind the calculator here it is. It’s simple enough to use in a spreadsheet or calculate by hand. Note, that this equation yields wine alcohol content as a percentage of alcohol by volume. There are other equations for alcohol by weight, however, wine alcohol content by volume is the most prevalent way to report alcohol levels. Photograph by: Robert...

read more

Adding Potassium Metabisulfite to Wine

- Jun 12, 2013

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 to Calculate Potassium Metabisulfite Additions 1. Take a pH reading. The least expensive way to get a pH reading is with test strips. Test strips are quick and easy, however,...

read more