Specific Gravity and You

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After my last “high flying” post on why American whiskey is so problematic, I thought I’d bring things back to earth and teach some foundational concepts. This lesson was part of my consultancy, but my time is a little pressed so I’m not exactly out marketing it anymore. What is specific gravity and how far can we stretch measuring techniques to harness it?

I’ve long preached to distilleries that they should make a bunch of very small scale secondary products. Most all these business school types turned distillers think it is a terrible idea. It will dilute their core product, not strengthen it like I propose. It will confuse their sales efforts. It will confuse their investors. What no one seems to admit is that they have near no clue what the hell they are doing on a technical level and they need to practice on stuff. They also need to enrich their retail businesses plus benefit from new products having PR synergies with their core products (this last point is more powerful than anyone realizes). Many operations also need new retail scale products to help them retain top talent. I do not work in a distillery because no one has figured out how to properly pay me.

Before we get into it, a whole category of products simply does not exist (in practice) because firstly there are no dreams and secondly most new distillers have not figured out how to accurately vat complex multi component blends. I’ve seen distillers so frustrated by proofing that they bought bench top Anton Paar densitometers for startling money while their labs had near no other analysis equipment. Most new liqueurs are nothing but mono, no doubt both because of a lack of dreams and technique. Our understanding of vatting has not advanced an inch despite 10,000 bitters producers working in the territory. Whats up with that?

Specific gravity is the density of a substance compared to another which in most all cases is luckily just water. It doesn’t have to be water, but another reference might only be used in petro chemical industries and may be a yesteryear concept now that analysis procedures are different.

Specific gravity is basically density which is mass/volume. g/L

If you know the density, the mass can tell you the volume and vice versa. Distilleries typically use this with quite large scales weighing entire barrels to gauge them. This also becomes conversely very useful on the small scale or anywhere in between when the containers become tricky. There are techniques to measure the density of mere drops of essential oils.

A hydrometer is the distiller’s go to specific gravity tool, but it is often the least appropriate option. Cheap, fast and good, pick two. Hydrometers are cheap and you can own a ton for a fraction of the price of great scales. You can stick one in a fermenter and get a quick reading without making a mess of glassware. You can stick a hydrometer in a still parrot and get inline continuous measurements that can become actionable such as starting or stopping a run. Hydrometers typically, however, will never give a lot of significant digits.

Refractometers are a tool we should quickly get out of the way. They convert refractive index measures to either density or related measures. They are not exactly cheap, but they are fast and can work in challenging circumstances. They can also take a single drop and give you actionable advice such as when to harvest a crop. They do not provide many significant digits. I have low and high brix scale refractometers, but I use them far less than I used to. You cannot use them on alcoholic solutions.

The fine coffee scene has been loving digital refractometers lately, but it may not be their best option. Or actually it may, because of how companies like VST have made the advice so actionable (they even have an app!) Refractometers for coffee require filtration because particles obscure and haze the reading. Coffee is typically sucked through a syringe filter before it is put on the refractometer. Another method very useful to the distiller may actually serve the coffee scene well but so far it is not widely explored and we’ll get to that (I actually have a rare 1970’s text called The Coffee Hydrometer that I’ve been meaning to digitize).

The most accurate tool a distiller can use probably isn’t legal with the gaugers and that is why it is not practiced for tax work like proofing. The revenuers have long endorsed certified hydrometers and certified thermometers, but they are not exactly the most accurate.

The most accurate way to measure density may be with the specific gravity bottle (pycnometer) and a very good scale (and thermometer!) which is what many spirits researchers used in the old school. The bottles come in various sizes and are designed to hold very precise round number measurements (at 20°C). The bottle is filled to its neck and a special stopper forces excess liquid up a tube so at the top of a narrow aperture it hits 1.000 liters or some such number with confidence. Cheaper brands I’ve bought were never accurate (or my temp was wack?), but you can still calibrate them yourself though next time I’m going to spend money for quality. When your volume measure has significant digits your density measure is only limited by the quality of your scale. My favorite scale vendor is Old Will Knott. I’m glossing over temperature, but modern sous-vide immersion circulators make it much easier to control for. If you need all the significant digits, a liquid can be held at constant temp before it is put in the pycnometer and weighed.

I have done a ton with scales. Remember, I developed the idea that you can weigh carbonation for sparkling beverage production with a kitchen scale.

We can walk all those pycnometer concepts down into practicality. An outstanding distillery tool is the 5 mL automatic pipettor (5000µl). They are about $70 and can be paired with a $100 jewelers scale to get many significant digits. Their repeatability is excellent and can be tested. A portion of liquid can be put on a scale and the pipette tip primed then liquid zeroed (youtube is full of technique). A 5 mL amount can be removed twice to prove repeatability and get the measurement into base ten (10 mL) so density is easy to calculate.

Density should be recorded constantly in competitor analysis scenarios. Basically everything that comes through the shop. With the printed alcohol content, sugar content of liqueurs can be extrapolated or the slighter measure of obscuration investigated. This is important for vintage spirits where you want to get an idea of either sugar content or obscuration, but you don’t want to destroy a large sample. With a density measure and then a 5 mL sacrifice to dehydration lots of vintage spirits can be investigated for alcohol content in their current state and obscuration in their pre-ullage original state (Weigh the bottle before you open, weigh it again after you drink and empty it. Coupled with the specific gravity, you’ll know its volume in its present state and not mess with your good drinking. Never put that stuff in a graduated cylinder). So much vintage booze is being consumed where we would all benefit from rudimentary 5 mL sacrifice analysis projects.

The pipettor process will likely work for coffee quite well with no filtration. The 5mL pipettor can also be used to fill tasting room glasses for nosing and gratis scale samples. The pipettor with its digital scale can also be used to rapidly assemble different generation of vatted products in 100 mL or less batches. Precision at 100 mL means you can quickly assemble ten prospective generations of a recipe for assessment progressing a single variable at a time. You are left with no reason to not see ideas fully elaborated. I also create sketches, but more on that some other time.

The most profitable idea I’ll share is the rule of 1.587 which is the density of sucrose (or 1.59 if you don’t need that many significant digits). The density of sucrose can reveal how much volume a mass of it takes up and thus reveal other measures we need to hit certain targets.

If we are making an Amaro that we know we want to have 280 g/L of sugar and 24% alcohol, what do the parts look like? What volume will the sugar take up? 280 / 1.587 = 176.43 mL. So the sugar free rest of it has a volume of 823.57 mL. Now how much alcohol does that start with if it is going to be diluted by sugar to 24.00% on the revenuers nose.
(823.57 * X) + (176.43 * 0) = 1000 * 24.00.
(823.57 * X) = 24,000
X = 29.14

That 823.57 mL is going to be a vatted collection of individual concentrated components. As they take shape, they can be shifted, subdivided, even combined. Certain components may bring a sugar content that needs to be deducted from the 280 such as a fruit juice. Pretty soon you’ll have a spread sheet.

Some components may exist in such small quantities that a hydrometer just isn’t going to work, but you still should know the specific gravity of everything so the SG bottle or pipettor must be used.

Now you have to scale it up. Sometimes this is to roughly five gallons (tasting room) and maybe to 500 or so gallons (wholesale). You should have a plan for the order of operations in which you combine components that harnesses all your available scales to quickly get you to a target with confidence. Proprietary narrow range hydrometers could be used to quickly check your work (and check off sheets made in case the phone rings and you walk away, but SG knows all). Eventually a final check has to be made and a plan for correction. The final point of concern is percent alcohol to satisfy the revenuer so either water has to be added or concentrated ethanol. The added sugar should be very easy to hit accurately so the error is most likely with the alcoholic quotients. Any addition to average up or down the alcohol content will have to preserve the sugar content so sugar might need to be added to your bump.

These operations should be practiced at different scales and employees should be given sample puzzles to solve before they risk expensive ingredients. This is basically the premise of my distillers workbook exercises.

Elaborating a vatting procedure can keep you safely away from all in the pot cooking and push you firmly into the progressive process. Fragmentation of the product is literacy in the product. Ideas can move towards deeper involvement.

The amaro challenge can push beyond mere assembly for a distiller and into wielding special effects to create sensory differentials and tone refinement to push expressions from ordinary to extraordinary. Every distillery should have an Amaro and it should be a measure of their relationship with beauty and capacity for abstraction.

None of this is too complicated, but none was spelled out in educational books for distillers. Modern texts only teach the maintenance and continuation of large scale products, not the origination of small scale products. I have used this all to develop two notable products on the market that have done more than $300k per year in wholesale revenue. One is more than ten components while the other is merely three, but extrapolated all the way from a single cocktail to a nearly 250 gallon batch. I’ve developed countless others that exist only as one-offs or as proof of concepts in the event extraordinary source materials become available.

Good luck!

As far as data tables goes, for the specific gravity of sugar solutions, the data table I’ve used the most is C440. For ethanol solutions, it comes from a text because most do not have the full range at the lower ethanol contents which becomes important to certain types of work. Your vatted projects may never require charts, but you will definitely need them for competitor and role model analysis when you want to become hip to the common structures liqueurs and amaros take. If you use a great resource, please share it up.

Advanced Emotional Content Basics (liqueurs!)

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Advanced motional content basics (liqueurs!)

I apologize for this chart rendering so poorly in the browser.

Type & brand alcohol specific gravity alcohol influence on specific gravity adjusted gravity sugar in g/l
carlshamns flag punsch 26 1.082 0.03022 1.11222 293
suze 20 1.031 0.02404 1.05504 143
amer picon 21 1.031 0.02504 1.05604 145
amerpicon (beer?) 21 1.066 0.02504 1.09104 237
cynar 16.5 1.081 0.02054 1.10154 265
stock sweet vermouth 16 1.044 0.02002 1.06402 167
stock dry vermouth 18 0.02206
cointreau 40 1.036 0.04822 1.08422 219
brizard apry 20.5 1.121 0.02454 1.14554 381
maracuja do ezequiel 26 1.098 0.03022 1.12822 336
china martini 31 1.104 0.03582 1.13982 366
villardi jabuticaba 25 1.105 0.02916 1.13416 351
constelacao licor cafe 27 1.139 0.03130 1.17030 457
j. monteiro mint licor 22 1.171 0.02605 1.19705 520
carpano antica vermouth 16.5 1.057 0.02054 1.07754 201
campari 24 1.066 0.02811 1.09411 245
citronge 40 1.073 0.04822 1.12122 317
disarono amaretto 28 1.084 0.03240 1.11640 304
marolo chamomile grappa 35 1.025 0.04092 1.06592 171
punt y mes 16 1.073 0.02002 1.09302 242
matilde poire 18 1.115 0.02206 1.13706 358
lemoncello “torna sorrento” 30 1.059 0.03466 1.09366 245
senior curacao of curacao 31 1.044 0.03582 1.07982 208
marie brizard curacao orange 30 1.090 0.03466 1.12466 325
nocino maurizio russo 30 1.039 0.03466 1.07366 191

One of the most significant contributions to the emotional content of a flavor experience is the sugar content. An understanding of sugar content can be useful in creating commonly accepted harmony. Harmony in this case is a function of sugar content relative to numerous contrasting planes like acidity and alcohol. Unfortunately there isn’t much reliable data out there on sugar contents yet, but I constantly see search referrals looking for them (calorie counters or inquisitive artists?). This table (it will grow) represents an attempt.

(Gary Regan has an excellent table and maybe I can have him send me alcohol contents for products at the time he made measurements (because brands do change their metrics) and then I can crunch the numbers and we can see how products have evolved (if we are confident in our methods!))

Within a liqueur, two significant forces (there are others) effect the density which we can use to get a really close approximation of the sugar content (feel free to challenge my methodology). Alcohol decreases density and luckily its a known variable because its printed on the label (but allowed to have a fairly large margin of error). Sugar increases density and its the unknown variable we are looking to reveal.

If we compensate for alcohol’s effect on the specific gravity using one of many available tables, we can create an adjusted specific gravity that can be used to isolate the sugar content’s effect. To find various alcohol contents’ influence on the specific gravity, I recommend the chart in the back of Irving Hirsch’s “Manufacture of Whiskey, Brandy & Cordials” (1937 reprint). Hirsch’s chart (courtesy the Bureau of Standards) is the best I’ve found. Many others do not feature the low alcohol contents with any accuracy that are needed for examining aromatized wines.

The adjusted specific gravity can be converted to a grams per liter of sucrose using “circular C440” from the same Bureau of Standards. This circular used to be easy to track down in PDF but all my links are broken and I’m too low tech to host it. I can email the PDF to anybody that needs it.

Of course I should be paying attention to temperature which influences gravity, but most of these measurements were taken on the run in adverse circumstances that didn’t allow a temperature consideration (the free minutes in between restaurant service here and there).

This data has a variety of uses. For starters we can compare these numbers to many of Joseph Koenig’s from 1879 and make some anthropological hypothesis as to why things have changed. Tastes have changed of course, but in the beginning did liqueur sugar contents ever match popular tastes in the first place? Recipes were dynamic as opposed to the modern static attempt, but was that because liqueurs didn’t always bring the desired emotional content to allow harmonic recipes using our modern simple ratios (2:1:1)?

We as artists can use this data as a tool to increase empathy. Selecting bottlings based on sugar content can help control and focus the emotional content of a drink. Aroma aside, a change from Brizard’s curacao to Senior’s curacao will result in significantly different emotional content in a 2:1:1 margarita.

Then of course this data can be used to produce house made products for a bar program. Why reinvent the wheel when you can simply emulate success? Most house made products I’ve tasted could benefit from a little more consistency and refinement.

Feedback please.

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Advanced Sugar Management Basics

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[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?
[I have totally given up on brix and now only use specific gravity]

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 sugar content.

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 gravity which does 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.

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Deconstructing Sweet Vermouth

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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 that can only really be found by using distillation.

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!).

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