So, What Is “Degrees Plato”?

WEDNESDAY 05/31/2017

To answer another frequently asked question in the store, “What does your name mean?,” today we are going to explore what degrees Plato actually means, and how it differs from other measurements associated with the brewing process.

Originally developed in 1843 by Bohemian scientists Karl Balling and Simon Ack as degrees Balling, later improved on by Adolf Brix as degrees Brix, and finally refined by the Normal-Eichungs Kommission and Fritz Plato as degrees Plato (still have no idea where they got the names for these measurements…), the Plato scale expresses the density of a solution as the percentage of sucrose by weight. Sounds complicated right? WRONG, it’s so simple. Simply, a beer at 12°Plato has the same density as a water-sucrose solution containing 12% sucrose by weight. Meaning that the solution is 12% sucrose, and 88% water. 0°Plato = Pure Water. 100°Plato = Pure Sucrose. Easy right?

So this is where it gets a little more complicated. Degrees Plato cannot be expressed when talking about beer without its relation to specific gravity or SG, the ratio of the density of all suspended substances (including but not limited to just sucrose) to the density of a constant (water). These aforementioned scientists first determined degrees Plato’s relationship to SG by preparing pure sucrose solutions of known strength, then measured their specific gravities and prepared tables of percent sucrose by mass vs. measured specific gravity. According to the handy dandy wikipedia, “The relationship between degrees Plato and specific gravity (SG) is not linear, but a good approximation is that 1° Plato equals four “brewer’s points” (4 x .001); thus 12°Plato corresponds to an SG of 1.048 [1+(12 x 4 x .001)].”The only reasons for the refinement of the measurements over the years were to find a more specific SG or degrees Plato. Balling measures to 3 decimal points, Brix to 5, and Plato to 6. Equipped with a Plato/SG table, a brewer can take their SG and determine the degrees Plato.


Now why would someone want to do that??? Well…not all substances can be fermented and wort (unfermented beer) is not just a concentration of pure sucrose in pure water. Plato is important to give a very specific account and measure of fermentable material in wort and therefore is very important in the brewing world.

At the end of the day, these measurements can be attributed to a beer’s alcohol by volume. Take the difference between the OG, the original SG pre-fermentation of a beer, and the FG, the final SG of the beer post-fermentation, do a little math, and you have your alcohol by volume. Now while SG is usually used at this point, the original Plato of a beer can help determine a brewers need for a certain volume of yeast and the timetable of fermentation.

Beverage makers of all kinds use a variety of these scales to determine their ABV. Winemakers as well as the sugar and juice industry typically use degrees Brix. British and continental European brewers generally use degrees Plato. American brewers use a mixture of degrees Balling, degrees Plato and specific gravity. Home brewers of wine, mead, cider, and beer makers typically use specific gravity.

So there it is, boom.