ABV, pH, & Sulfites

ABV: Alcohol By Volume:

I looked all over the internet for a way to figure the alcohol by volume (ABV) of my mead.  I found no less than 11 different ways to figure it with 11 different totals – and that was just using the gravity as a reading.  And that was in one hour of looking.  The one I use, which appears to be the closest to other valid measurements (such as the hydrometer’s potential alcohol measurements) and often yielded a result in the middle of all the readings is:

Original Gravity – Final Gravity ÷ 0.75 = ABV%

For example, my blackberry honey show mead had an OG reading of 1.100 and a FG reading of 1.015.  So: 1.100-1.015 = .085.  Then .085 ÷ .75 = 11.33% ABV

Keep in mind that other countries may figure alcohol by weight (ABW) instead of ABV.  That formula is OG – FG/ .789.

pH

The required pH of mead is even less clear if you look it up on the internet and can be especially difficult to control and measure for the home meadmaker.  However, it is important.  Very important, but it appears to often be overlooked in the many mead recipes I have found on the internet.  The pH influences the stability of your mead, the color, flavor, aroma, how it ages, and myriad other factors.  However, it is also expensive for the home meadmaker to buy accurate pH equipment.  The wine pH test strips will suffice for us home zymurgists, but it is something that needs attention.

For yeast to thrive they need to have the right temperature, they need plenty to eat, they need to be free of sulfites, and their acid and pH level need to be controlled.  Remember that pH represents the ratio of acid and base in a solution.  Mead fermentations occur best around 3.6-3.7 pH.  This is higher (less acidic) than recommendations for grape wine.  This pH is influenced by the pH of the honey, your water, and any other goodies you stick in your must.  Therefore, testing the pH regularly as you add fruit is important, some fruit is more acidic than you think.  Plus, it is easier to increase the acidity than it is to decrease it, so add acid sparingly!!  This includes powdered acid you may add, or any acidic fruit.  Further, because adding acid as you go can have unintended consequences to your honey wine, it is best done early in the process.  Again, I fall back on the saying, “When in doubt, leave it out.”  If you are not sure whether or not to add acid – don’t. When you read my recipes you will probably notice I add a little acid at a time. I check the pH at each racking and let that, along with how it tastes, determine whether to add acid or not.

Aging and preserving your mead might be a different pH story.  Sulfites present in your mead help preserve it from the damage of oxygenation and reduce the risk of contamination from unwanted microbes.  As your mead ferments, the honey will throw off acid and lower the pH (usually).  This is good, because a higher acid level (and thereby a lower pH) will help preserve the wine.  I like my pH to be about 3.4 (below 3.5) before bottling, and it can go to as low as 3.0 (although below 3.2 might way too sour). This will make the mead more stable for aging. The “sweet spot” for pH varies, but is considered to be 3.2 to 3.6. This allows it to be piquant and age safely (low chance of turning to vinegar or losing its color). Mead with a high pH (3.7-4.2) are not only more prone to spoiling over time, but may taste flat and lose their color.

**Note: the measure of pH ranges from 0 to 14, with 0 being the most acidic.  Therefore, the more acid you add to your must, the lower the pH number.

Sulfites or Sulfur dioxide:

Sulfur dioxide (SO2) is an antioxidant for your mead (and juice, musts, etc.).  It binds with oxidative products and lessens their negative effect on your mead.  It also interacts with the acid in your solution, with the acid making more SO2 available to fight nasty microbial reactions.  There are ways to measure SO2 in your wine with sulfite measuring kits, but that is typically beyond the home meadmaker.  Sulfur dioxide can be added to your mead by adding potassium metabisulfite (avoid sodium metabisulfite if you can – it will sulfite your mead, and it will add extra sodium, and who needs that?  Plus, you can taste it).  This can be found in Campden Tablets, which are premeasured to sulfite one gallon of mead, wine, or juice.  Some meadmakers use this on their fruit before pitching a melomel.  If you do, wait a full 24 hours plus, before pitching your yeast, or the sulfite will kill your yeast.  You can also buy potassium metabisulfite powder and use 1/8 t per gallon.  I prefer this method because the Campden tablets also have binding agents that do not dissolve well and create little floaties on the top of my mead.

To use sulfites, add it to the carboy at each racking after your primary fermentation has completed.  This is necessary because the SO2 will dissipate over time and become unproductive in protecting your mead.  Plus, each time you rack (every 3 months or so), it exposes your mead to oxygen, which is the enemy.

“But I’m allergic to sulfites.”  Really?  Can you drink any type of alcoholic beverage without ill effects?  Can you eat most name brand lunchmeats? Salami? Processed fruit juices? Packaged seafood? Dried fruit?  All these contain sulfites.  It is rare that someone has a true allergy to sulfites, and all wines and beer contain sulfites because it is put out during the fermentation process by the yeast.  I do put that my mead “contains sulfites” on my label in case any of my friends are concerned.

Advertisements

2 responses to “ABV, pH, & Sulfites

  1. Actually, most Campden tablets have sodium metabisulfite as their active ingredient.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s