top of page

Has the International Riesling Foundation Misled a Generation of Consumers?

by: G. Reese E'Spoon


The International Riesling Foundation (IRF). What is it? Who is behind it? And does it promote nothing but misleading nomenclature whose purpose achieves the opposite of what it sets out to do—which is to help everyday wine drinkers buy a bottle of riesling based off its sweetness level?









I was first introduced to the IRF and its now-famous ‘scale’ (above), which wine producers slap on the backs of their bottles, at a tasting about six years ago. And until last week at another tasting, I had never questioned the scale’s accuracy.

The wine in question was a single-vineyard riesling from a producer in the Finger Lakes. On the back of its bottle is an IRF scale that listed the wine a hair-width away from the far-left wall of IRF’s scale, suggesting that it’s bone-dry. 

But upon tasting, the wine appeared off-dry. My guess was that its residual sugar (RS) sat near 10 g/L, and likely higher.

After the tasting I was curious enough to look more into the IRF on a site called What I found online was, essentially, nothing.


I was shocked.

In articles from previous years (2007-2016), the IRF and its unnamed spokespeople claimed “to increase awareness, understanding, trial and sales of Riesling wines through a comprehensive, integrated system of industry cooperation, research, trade education, and consumer communication.”

But the IRF no longer has a registered website (previously, and its social media pages have remained dormant since pre-pandemic times.

One blog post from 2008, the only listing I could find that set out to detail the IRF scale and how sweetness levels are determined, detailed (without citation, but it is assumed that the old IRF website is the source) the specifications for the IRF’s dryness levels. The following was pulled directly from the blog The New York Cork Report:

"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 pH 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."

….. what the fuq?

Why would any advocacy group, especially one in an industry whose ingredient transparency standard bearer is the Nutrition Facts label in the United States, list sweetness levels based off the acid to sugar ratio? How many millions of people, (how many freaking diabetics!) has the IRF’s scale duped since its inception in 2007?

Let’s start by addressing the first thing that came to my mind. By the IRF’s standards, fucking Coca-Cola (108 g/L of sugar) is dry. And Mountain Dew, Red Bull and the rest of them and so forth. This is because they draw the same pH as a fucking lemon. The sugar levels in these sodas, which equal sugar levels in Tawny Port, just attempt to mask the acidity and vice versa.

Wine, and most beverages for that matter, contains many types of acids that can deceive any drinker into thinking a wine could be drier or sweeter than it actually is.

Take Vouvray demi-sec, for example. Vouvray demi-sec is generally bottled with near-high acidity and an off-dry sugar content (4 g/L-12 g/L RS). When you drink Vouvray demi-sec, you may think the wine is dry because its acid structure is so piercing and zippy that it cuts through sugars and darts to taste receptors, stabbing at them and triggering them to send high-protein mucus to the scene as a shield against the acid, while your sugar receptors are less sensitive and remain in check. And without reminding yourself where exactly in the mouth sugars are tasted (primarily the tongue) and where acids are measured (primarily the sides of the tongue and far corners of cheeks), you may assess a wine with the structure of Vouvray demi-sec as ‘dry’ rather than ‘off-dry’.

So, in essence, the IRF and the wines whose producers I’m assuming pay money for the rights to use its garbage scale are driving drinkers toward false perception rather than what's important, what literally defines sweetness, which is a product's sugar levels. We began this custom not to determine whether a product tastes good, but to determine if a product might be deathly unhealthy for us to consume. By the IRF's standards, if a Riesling is balanced, it is dry. If its acids exceed actual sugar levels, the wine is automatically dry. And the greater the gap between a higher sugar reading to a lower acid reading, the sweeter the wine is, all of which is just wrong.

A final thing of note here is this:  riesling is naturally a high-acid variety, and its wines should show elevated acidity, even in moderate-leaning climates it’s sometimes planted in (Columbia Valley, Carneros, Baden, etc.). Many producers, even though the IRF has zero online presence anymore and its legitimacy is a mystery, still use its scale for their rieslings in 2022 bottlings—Chateau St. Michelle, Willamette Valley Vineyards and many prominent Finger Lakes producers are clients, as is a range of international producers. Its scale discourages producers from making rieslings that are naturally high in acid. It encourages the vinification of flabby products and perhaps even the inclusion of chemicals, synthetics and other additives.

The conclusion here is this:  the more wine you drink, it is probably best to seek outside interpretation less and less. Don’t judge a wine by its cute label, don’t read reviews, don’t order the heaviest 750 mL bottle at a restaurant just because it's the heaviest 750 mL bottle in the restaurant and don’t ever read sweetness labels on the back of bottles.

Also, if we need another reason as to why blind tasting is so important, look no further. A seasoned wine professional is able to see through all the horse shit.

***If anybody has more information about the International Riesling Foundation, please reach out with it. I was mainly motivated to write this entry because of an appalling lack of information out there. If any of my findings are inaccurate, your criticism is welcome.***

bottom of page