Brix, Ph, and Acidity in wine – how to measure each.

Three measurements are often mentioned in winemaking: Brix, Ph, and Acidity. In this video, Wes Hagen of Clos Pepe defines each and talks about Birx levels in California, in German Rielsing, in Champagne, and in the Rhone Valley. This is a useful video for WSET students and anyone trying to better understand winemaking.

We filmed Wes at Pinot Days in San Francisco in 2009.

Our Wine Education 101: Grape Varieties series is here: https://www.youtube.com/playlist?list=PLddUmDhg4G_JlCX2ufjjgDXYObtOM39Hz

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Video Text:
Brix is just basically the soluble percentage of sugar by volume. So if a grape that you buy at the grocery store is about probably the same level of sugar content as grapes picked for champagne; 18 19 20 degrees Brix.

So use the idea of the Thompson seedless as your baseline for about 20 brig. Sugar in grapes as it really a fully ripe wine grape taste more like sugar than are like candy than produce very very extraordinarily sweet. So if you are wondering are these grapes ripe chances are they’re not ripe. I find that a truly ripe grapes screams “pick me”. So Brix for me 23, 24 barely over 24 is perfectly appropriate for picking my estate wine. Like I said champagne 19 to 20 (brix), European wines sometimes you know depending on a Riesling can be down in the teens all the way up to really ripe years in the Rhone you may see 24 degrees Brix.

Amador when you’re talking about you know really ripe Zinfandels you may see 26, 27 degrees Brix. Generally 0.6 is the conversion factor of bricks to alcohol so if there’s 10 degrees Brix you have 6% alcohol 20 degrees Brix is 12 percent alcohol and so on and there’s a little bit of wiggle room and there depending on the yeast to use and such.

Let’s talk about pH now without getting too geeky pH is a measure of hydrogen ion activity in solution, which just means how fast are the little hydrogen ions flying around in the solution. Which it’s very important to understand the mouthfeel of the wine low pH means more acidity high pH means less acidity but it actually is more of a measurement that those the activity but it generally means low acid / high acid.

It’s an inverse relationship with acid so lower the pH higher the acid pH in white wine like I said, probably like 3.2 to 3.3 is what I like in white wine; nice structure beautiful acid. Red wines … if a soft red wine is probably 3.5 to 4 point pH a red wine like Pinot Noir or Gamay more acid should be between 3.3 and about 3.6. So most wines you’re tasting if you think that are soft or above 3.5 pH and most ones that you’re tasting that you think have good structure and acidity are probably under 3.5, so 3.5 is kind of where I separate a soft wine from a structured wine. Structure meaning acid not tannin.

And then lastly you asked about acid. Well acid is usually mostly malic acid and tartaric acid. Malic and tartaric have a relationship where malic has a bright appleI flavor and tartaric acid is more the the acid flavor that we’re used to in wine; slightly minerally and slightly metallic.

So the the malic acid is usually removed from the wine by a bacteria and the bacteria consumes the malic acid and excretes lactic acid and the lactic acid gives the red wine sort of soft round kind of character to it and it also mellows out acidic wines like Pinot which takes very Gamay like before they go through malolactic fermentation. And end up being a little more seamless and a little more minerally and not so bright brightly purely fruit driven.

So I’m a big believer in malolactic for all red wines except nouveau Beaujolais and I’m a big believer in malolactic fermentation for Chardonnay but not for Sauvignon Blanc. A lot of Riesling is even in Germany do go through malolactiC. Chablis, surprising when I went to Chablis, I found out all Chablis also almost all do go through 100% malolactic.

There’s some regions that make very soft Chardonnay that want to maintain acidity so they make a non malolactic Chardonnay but I think the process of taking the out malic acid out and promoting lactic acid in the wines I make is vital to the mouthfeel and what’s happening. And it changes the acid structure a little bit as well but acid is measured in the weight of the acidity in the solution as opposed to pH which is a measure of the activity the ion activity within the solution. So acid is fixed and pH is actually about activity and I think it’s if you’re going to understand as acidity or pH in wine, then pH is the way to go because it influences more in the way that the wine tastes and the way the wine reacts to your taste buds.