New guidelines recommend four sweetness (or should it be “dryness”?) categories for Riesling; dry, medium/dry, medium/sweet and sweet.

We’ve all done it. Bought a bottle of Riesling we expected to be dry and found it to be sweet – or vice versa. My local wine store carries 39 Rieslings. Seven of those give some indication of sweetness – three of those are misleading.

Now an American-based organisation with international membership, International Riesling Federation (IRF), has come up with a recommendation of four sweetness levels calculated after considering three major factors that affect our perception of sweetness in wine: residual sugar (RS), total acidity (TA) and pH. They do not include alcohol level and how it relates to sweetness, and the form of sugar (glucose, fructose etc.) in how we perceive the sweetness.

The technical details are at the end of this article, but let’s see what category some well known local Rieslings would fall into. Listed below are the technical data that determine the sweetness level according to the IRF together with my assessment of each wine’s sweetness (a tick means I agree with the IRF).

You can check my calculations using the guide below.

Let’s look at the two wines where I disagree with the IRF classification.

Villa Maria 2007 Cellar Selection would normally fall into the medium/dry classification because it has an acid to sugar ratio of 1.22 (sugar divided by acidity). Dry is under 1.0 while Medium/Dry is 1.0 to 2.0. However because the wine has a pH level below 2.9 (it is 2.87) it drops down to the Dry category. To my taste the wine is only just Medium/Dry so one of us is not far out.

The one serious difference is Felton Road 2007 Riesling. To my taste the wine sits on the dry side of Medium/Sweet and yet it clearly falls into the IRF’s Sweet category. I asked Felton Road winemaker, Blair Walter, what he thought of the IRF classification.

“I would have a problem putting “Sweet” on that label’, he replied. “When I ask visiting wine experts to guess the residual sugar on our Riesling most pick it as 12-15g/l with a few going as high as 20-25g/l (the wine is 47g/l). I don’t know what it is about the wine, perhaps its strong mineral characters add to our perception of dryness”.

Blair was also critical of Felton Road Block 1 Riesling being in the same class as ultra-sweet, botrytised Riesling. He suggested that there should perhaps be a pecking order within the sweetness category to distinguish the barely sweet wines from super-stickies.

The IRF classification at least draws a line in the same. It’s also fairly simple to decide what classification a wine fits into providing you have the technical data. No doubt it will be refined as the IRF gets feedback from winemakers and wine drinkers but it’s a great start

Now, what about Pinot Gris …?

International Riesling Foundation

Final Proposal on Riesling Sugar Guidelines

The Scale

It is proposed that the International Riesling Foundation supports four sweetness categories for Riesling, as set forth below, using no numbers to designate the various categories. They will be referenced only by the terms we used for each of the four categories. Wineries are encouraged to use these categories on all their literature and labeling as well as verbally as a guide for wholesalers, retailers, restaurateurs and consumers.

In the following list, sugar and acid are listed in grams per liter.

The proposal is as follows:

Dry. Here the ratio between acid and sugar would not exceed 1.0 acid to sugar. For example, a wine with 7.5 grams of acidity and 6.8 grams of sugar would be in the same category as a wine with 9.0 grams of acid and 8.1 grams of sugar. Similarly, a wine with 12 grams of sugar and 12 grams of acid would be dry.

Notice also that wines that are totally or “near-totally” dry (such as 4 grams per liter) will have a much lower ratio. For instance, a wine with only 3 grams of sugar and a total acidity of 6 grams per liter will have a ratio of .5, and clearly the wine is dry.)

As to pH: we assume that the range of pHs for most Rieslings is between 2.9 and 3.4. So 3.1 is the “base” pH with which most wine makers will be working. So if the pH of wine is 3.1 or 3.2, it remains in this dry category. But if the pH is 3.3 or 3.4, it moves up to Medium Dry. (And if the pH is 3.5 or higher, the wine maker may wish to move the wine to Medium Sweet.)

Medium Dry. Here the ratio is 1.0 to 2.0 acid to sugar. Example: a wine with 7.5 grams of acid could have a maximum sugar level of 15.0 grams. And if the pH is above 3.3, it moves to Medium Sweet, and if the pH is as low as 2.9 or lower, the wine moves to Dry.

Medium Sweet. The ratio here is 2.1 to 4.0 acid to sugar. Example: a wine with 7.5 grams of acid could have a maximum sugar level of 30 grams. And again, the same pH factor applies as a level two wine: if the pH rises to 3.3, you move up to Dessert, and if the pH drops to 2.9 you move to Medium Dry. And if the pH is 2.8 or below (highly unlikely), the wine could be called Dry.

Sweet. Ratio above 4.1, but using the pH adjustment, a sweeter wine with a ratio of, say, 4.4 might actually be moved to Medium Sweet if the pH is significantly lower.