Advanced Sugar Management Basics

[Keep in mind how old this is. I leave these around to show where I have been and when.]

For a while I’ve been trying to learn more about what I drink through quantitative beverage analysis (it also might come in handy as a wine maker or distiller some day). Curiosity really built up over so many occasions of tasting wines and getting into arguments if there was residual sugar or not. I wanted to prove that the wine in question had negligible unfermented sugar and therefore the “sweet” sensation was due to other variables. Answering specific questions like how dry are dry wines led to wanting to measure the structural variables of any mystery liquid. How would I model a fruit wine I was making myself or understand a liqueur I was trying to replicate.

With sugar content, when a solution contains both alcohol and water, tools like hydrometers and refractometers need adjustments to have meaning (brix refractometers over estimate sugar in the presence of alcohol and brix hydrometers under estimate sugar), but what are the correlations? and who has already constructed all the necessary empirical charts that are needed to make corrections?

One way to find the sugar content of an alcohol containing mystery solution is to distill off the alcohol and dilute it back to its normal volume with distilled water. I’ve done this before in previous posts and though it works, its a bitch. It also over engineers the problem if you already know the alcohol content confidently which in the case of commercial liqueurs is by law printed on the label. Distillation also destroys the sample. (I will point out that there is also a crazy way for dessert wine makers to analyze their wines by using a formula that uses the over and under estimates of both a refractometer and a hydrometer).

When you know the alcohol variable you can easily use a short range hydrometer to find the sugar content of any liqueur bottling you posses (and maybe without even having them) without destroying product. This is simple because sugar increases specific gravity and we know by how much because there are lots of charts and the opposite is true of alcohol of which there are charts as well. If you find the effect the alcohol has on obscuring the specific gravity from revealing the true sugar content, the effect can be added to the obscured measure to reveal the true brix.

If it isn’t clear, the benefit of all this measuring is to either produce intuitively used products based on favorite models or to create relationships between products for the fun of intuitive substitution (you cannot easily substitute liqueur 43 for lillet because the sugar model is so different but you probably can substitute pineau de charentes or even st. germain for lillet). The other benefit is to reduce drink prices (or increase drink profits) by creating successful house made recipes with ingredients where you have a comparative advantage. If you have a walnut tree in your back yard you can probably make nocino cheaper than buying it. Modeling the sugar and alcohol content of great commercial nocino can help make yours great (intensity of aroma will be your only tough to crack variable). You will be able to celebrate walnut cocktails cheaper than anyone else and your celebration will be awesome because the intuitive modeling helps reveal the trees terroir relative to another.

One way to start measuring things if you are lazy or lack the requisite hydrometer is to look at specific gravity tables of commercial products that exist all over the web. These tables were all created for the sake of layering liqueurs in pousse cafes. Gary regan’s (the link breaks periodically but is from books.google.com) is by far the best though it should be considered that many brands (d)evolve over time. Regans’ chart expresses sugar relative to alcohol so because its not yet a useful number you simply add the specific gravity influence of the alcohol listed on the label which can be converted with this chart (which also periodically breaks). Once you find the specific gravity of an alcohol water solution that has the same proof as the liqueur, you add 1.0 minus the specific gravity of the particular ratioed alcohol-water solution to the obscured gravity to get the true sugar content un-obscured by alcohol.

Unfortunately your not out of the woods yet. You are still dealing with specific gravities which do not mean much to a pastry scale. To convert specific gravity to g/L or brix you can use the “circular of the national bureau of standards C440″ (easily googled to find the indispensible PDF) for easy conversion.

So now with the alcohol printed on the label and one narrow range precision hydrometer you can figure out a sugar content in under three minutes! No refractometer, no distilling.

(Another way to find the density without using a hydrometer is to simply use a kitchen scale) because density = mass / volume. This method can be useful for dealing with volumes too small for a hydrometer though accuracy is sacrificed.

Deconstructing Sweet Vermouth

My aim here is to sacrifice a bottle of Stock’s sweet vermouth to learn something about it. Most importantly its official sugar content unobscured by alcohol, what can only really be found by using a still.

Before distillation and separation of the alcohol, the vermouth’s brix can be tested obscured by its alcohol content to see how much it throws off the hydrometer (11.25 brix). Most people’s understanding is that sweet vermouths are much higher in sugar so maybe the alcohol (16%) throws the hydrometer off more than I thought (I really just estimated the reading would be off one or two percentage points).

I put the vermouth into the still with an equal volume of water to essentially split it in half. The half left in the still is sugar, water, acid, and whatever aromatic compounds do not distill. What comes through is alcohol, distilled water, and what ever aromatic compounds that are volatile.

After the run and re-cutting what was left in the still to the original volume with distilled water (because a small volume escaped the system) the hydrometer shows a reading of 15.5 brix. This result seems likely because it is within Maynard Amerine’s guidelines for sweet vermouth.

Now we have something intuitive to shoot for in our home made vermouths.

During the run I was also able to taste the distillate as it came out of the the still. The results were very cool in that it smelt exactly like it does out of the bottle. You do see some of the separations of the botanicals as they move through in waves. The orange phase is the most distinct and intense showing how important shades of orange are to a sweet vermouth. I thought I noticed a whisper of vanilla along the way that I never tasted before in Stock and towards the end I noticed heavier wormwood-maybe herb-like aromas.

Now the 15.5 brix measurement of sugar can be translated to grams/liter so we can think of it in another way. With the help of the grams/liter translation, the volume the vermouth’s sugar takes up when dissolved can be found so that we can solve our two variable equation for sugaring and fortifying our wines to stock’s 16% alc. y 15.5 brix model (port often uses a 18% alc. by 6 brix model so if you substitute it for vermouth you will need to compensate with extra sugar for a drink that isn’t too dry!).

A formula that I’ve come across but never really used is weight in g/L = sg * brix * 10

brix 15.5 = SG 1.06326 so —-> g/L = 1.06326 * 15.5 * 10 = 164.8 g/L

Which is 5.81 oz. if you can’t handle metric

(what is interesting is that the tables in the back of Daniel Pambianchi’s Techniques in Home Wine Making show different results. His would be higher by more than 20 grams. So did I go wrong anywhere? I used the Circular of the National Bureau of Standards to get my specific gravity for 15.5 brix. The circulars table also computes the g/L of sucrose so it is an awesome resource to the liqueur maker.)

Now we can see what 164.8 grams of sugar looks like undissolved volumetrically in an oxo measuring cup. using whole foods organic sugar it looks like 3/4 of a cup (different sugar types will make it vary slightly).

When dissolved this will compress. but by how much? Supposedly there are wine makers tables for such things but I haven’t been able to locate any. Pambianchi does note that adding 250 g to 1 liter of water yields a new volume of approximately 1.2 liters.

A useful table may not be that important since we are primarily going to be using the same sugar content over and over. We can probably rely on a one time experiment with sugar and water.

A sugar-water solution and my scale shows that 164.8 g/L dissolves and compresses to become about 86 milli liters in volume (2.9 fluid oz.)

This gets us closer to how much we have to over fortify the wine to bring it back to 16% when sugar is added. More algebra could solve it exactly but the numbers are looking round and it should be noted that alcoholic beverage labels, even on wines, are allowed to have a one percentage point margin of error so if it was really 17% alc. but printed as 16% alc. they would be off by more than 5% and be okay. We could just fortify to 17.5% before we add our sugar and be done with it (we don’t even know how accurate the wine we use to start is anyhow!).

My understanding from Amerine’s books is that we want as little alcohol as possible so our beverage will not be hot tasting or cost us lots of tax money. Sweet vermouths commonly are 16% alc. while dry vermouths are usually 18%. Being over 16% alc. puts both over the very important acetification point (vinegar bacteria) but sweet vermouth may be able to be slightly lower because its large sugar content protects it from various other lactic bacterial spoilage thresholds (I really don’t know but 18% is a key number for those). Another reason for the differing alcohol contents could be because within a producer’s production process, both sweet and dry (before they are aromatized) come from the same fortified wine stock. The volume of the sugar in the sweet dilutes the alcohol to 16% (with an accepted one percentage point margin of error!).