Cider Class: Cider Laboratory

Back in May, I attended a wine conference and listened to a lecture about testing the level of acid in wine. At the end of the lecture, the presenter gave a demonstration of how to use basic laboratory equipment to do it, but I was unfortunately sitting in the back, and the demonstration was not projected nor was the presenter elevated on a stage. It was very frustrating to me.

Well, this last week at my cider class with Peter Mitchell was much much better.

Mitchell went though and talked about pH and how ciders between the pH of 3.2 to 3.8 taste better and are less likely to develop infections, with the ideal pH around 3.5. We then got to test apple juice for pH using the strips that I use and also an expensive pH meter.

From there, Mitchell talked about the total acid content in the juice, and gave a demonstration at a small laboratory station on the technique used. The idea behind it was that if the pH was too high, the acid content would be too low since the more acid there is, the lower the pH would become. By testing the total acid, one could make a calculation of how much malic acid, the primary acid found in apples, to add to lower the pH.

pH is also important when working with sulfites. Sulfites have been used since ancient times when water with sulfur was probably used for cleaning and discoveries of how little infections would set in. The thing is, the lower the pH and the more acid that is present, the less sulfite is needed to prevent infections. To add more sulfites would just be a waste of money.

So after we found out our pH, we added sulfites based on our findings. Thing is, sulfer disappates after time, and some people are allergic to it so there are government regulations of how much can be present in cider, so tests need to be run to insure the cider does not become infected while not harming people. Once again, I actually got to run this experiment in the lab. Got to love hands on experience!

Mitchell recommended using the book Chemical Analysis of Grapes and Wine: Techniques and Concepts published in 2004 as a guide to help set up a cider lab.

Read the Labels

I was poking though my freezer a few months ago and discovered several packages of peaches my mother has bought, cut up, and froze for me. I got out my copy of The Joy of Home Winemaking by Terry A Garey and looked up how to make a peach wine. Well, things didn’t go so well.

First off, I needed to put the peaches in a mesh bag, and put that in a primary fermenter and let them sit for a week with yeast. I didn’t have a primary fermenter, let alone a small one, so I used two juice pitchers and plugged the spouts with cotton balls to mimic something like an airlock, as sometimes the books say to use a cotton-wool bung. I have asked my local supply store for a cotton-wool bung, but sometimes we just don’t see eye to eye, and this is one of them. They didn’t have any.

Originally, I made up a batch and realized I over sugared it, but then I realized it wouldn’t fit into one pitcher, so I split it into two pitchers, added more water and peaches, and figured out the potential alcohol of each. Then I took the pH of both pitchers. My first batch of apple wine called for the juice of two lemons or some concentrate lemonade to lower the pH. This time, I went with lemonade, and got my pH to the desired level.

At the end of a week, I was suppose to remove the peaches and put the remaining liquid into a glass jug and fit it with an airlock. I went to test the potential alcohol at this time to make sure things were progressing as they should. I got the exact same number as when I started, which meant that the yeast did nothing for an entire week. Something was very wrong.

My hypothesis is that the lemonade I added to lower the pH contained some sort of preservative, which killed the yeast, and no amount of fussing with it would make it alive to start fermenting. When I bought the lemonade, I checked the ingredients on the label, but I’m not completely convinced there wasn’t any preservatives present. Since then, I have bought a powdered acid blend to lower the pH from my supply store, and any time I buy juice or processed fruit, I make sure it specifically says no preservatives.

Wine & Cider pH

When I was describing the differences between making beer, wine, and cider, I mentioned that they have different pH levels. A quick refresher, pH is measured on a scale of 0-14, where 7 is the middle and is neutral, such as water or milk. Things above 7 are considered basic, such as baking soda, lye, and chlorine, and things below 7 are considered acidic, such as lemons or vinegar. Now, beer, wine, and cider are all acidic, but to different degrees. In my case, I need to make wines and ciders in the 3.2-3.8 pH range. Anything more acidic (less than 3.2) will make it taste funny, which is what could be plaguing my cinnamon cranberry apple cider. Anything more towards neutral (greater than 3.8) could allow bacteria to grow and also have off flavors

Wine supply stores sell pH testing strips, which are great to have around. If the batch needs to be more acidic, lemon juice or acid blends also available at supply stores will help lower the pH. If the batch is too acidic already, the best advice is to try and find other fruit that is less acidic to averaging the pH of the batch.

I am aware that grape wines have three different kinds of acid already present, and that only one of those acids are really desirable, so there are special kits to test for this. However, other fruit do not contain all three of these acids, and so a simple pH test is all that is really needed.