One of the biggest challenges most home cider makers face is finding apples that will provide sufficient phenolic compounds. The answer to the problem is often literally staring us in the face. It is the apple peel. “Apple Phenolics” is my attempt to guide home cider makers on how much peel to include. The baseline will be a single variety cider made from Harrison apples, which is historically supposed to be one of America’s finest cider apples. The Harrison can have 122.4 ug/g of total phenolic compounds in the flesh(1). I’m assuming a 50% yield on the flesh to juice weight or 61.2 ug/g of juice. That is 0.0612 grams of phenolics per liter of juice. Yes, not all phenolics are the same and they are lost during processing but this is the baseline I used to see if it makes sense. How many grams of GoldRush peel would be needed to generate the same level of phenolics as Harrison cider?
Following the above logic, GoldRush will give us 0.0236 g/l from the flesh so we need an additional 0.0376 g/l of phenolic compounds. The peels of the GoldRush contain 265.3 micrograms of phenolics per gram of peel and I am assuming we extract 100% of these. Therefore, each gram of peel will add 0.0002653 grams of phenolics. That means I need 141.7 grams of GoldRush peels per liter of juice (0.0376/ 0.0002653) to give my cider the same amount of phenolic compounds as a single variety Harrison cider.
This is where the art and science of cider making intersect. 141.7 grams per liter would be almost 539 grams per gallon. I have generally been using 75-125 grams per gallon with very positive results and contributions. Maybe I should be using more peels or maybe it’s not about total phenolic compounds but specific types. Maybe I should calculate the addition based on the total chlorogenic acids or the procyanidins. I do know that when I have used higher amounts (~500g/gallon), I can get excessive amounts of proteins because I get protein haze. I also get high levels of color transfer from anthocyanins. I also get wonderful aromas and good mouthfeel that is mostly astringent. I am not experiencing excessive bitterness. We have to remember that the fermentation process generally decreases the amount of phenolic compounds and its a very dynamic process. i would need some expensive equipment to truly tell so for now, I am relying on my taste buds. I hope ”Apple Phenolics” will give you more data about apples and ideas on how to use utilize all of the apple to make better cider. Look for additional apples in the coming weeks.
(1) K.A. Thompson-Witrick and associates, Characterization of the Polyphenol Composition of 20 Cultivars of Cider, Processing, and Dessert Apples Grown in Virginia, J. Agric. Food Chem. 62, 2014
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