The Undegooglables
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Episode 91 · May 1, 2021

Specific Gravity

The hosts try to work out why alcohol strength is measured in "proof" and whether it's related to proofing bread.

“I love how this came down to specific gravity. I was like, these are a bunch of dudes making prohibition stuff, but nope.” (14:56)

Questions

Where does "proof" in alcohol come from, and why is it double the ABV? (00:32)

Our guess
A code for bootleggers or a way to cut grain alcohol, linked to "proving" as in yeast proving in bread.
Reveal the answer
The answer
Dates to 16th-century England, where spirits were taxed by a burn test (alcohol that ignited was "over proof"). In 1816 England defined 100 proof by specific gravity (about 57% ABV), and the US simplified it to exactly twice the ABV. "Proof" comes from the Latin "probare" (to test), and bread proofing shares that root.
Verdict partly

Listen to the episode

Transcript (auto-generated)
[00:00] Alright Coalson, we are taking a break from watching Pacer's Bulls games and now we need
[00:08] some questions answered. We got some under Googles for us this week. What do you got
[00:12] for us?
[00:13] Are we doing under Googles?
[00:19] That was the play of it.
[00:20] I'm super excited.
[00:21] You told us we had to.
[00:22] He said we signed up for it.
[00:23] In the end it's going to be better and more true than Google can give you.
[00:32] Well, so my buddy Mike, Mike Morrow, a fan of the show, sent me a text a couple weeks
[00:43] back and was like, what do you know about proof on alcohol? And I was like, well, he's either
[00:50] asking me because I'm his bartender friend or because I do the under Googles and I hang
[00:57] out with smarter people than I am. I actually did kind of know the answer to this one. And
[01:04] so I responded and then started thinking more about it and don't really know. So my response
[01:10] was that the proof on an alcohol bottle is twice the ABV, which is the alcohol by volume.
[01:21] And so I know that much. And my assumption always was that that meant that it was the
[01:33] alcohol versus another liquid. So like so the proof would be the amount of alcohol versus
[01:43] like a gallon of water or something. Right. So if you if if all the alcohol in it was
[01:50] not divided by other things, it would be that much alcohol in the bottle. Because otherwise,
[01:58] alcohol by volume is the only thing you would need, right? Why do we need another metric?
[02:07] The only other information I have from from my bartending experience is that the proof
[02:15] of things over 100 proof are very flammable. And that's the stuff you use when you want
[02:21] to light something on fire. And so I was like, well, I sent this back to him. And I thought,
[02:27] well, maybe I'm, you know, maybe I knew enough to answer his question. But that same week,
[02:32] my dad was making bread, and he was proofing the bread. And I went, is are these connected?
[02:40] And then the words proof? Is that connected to the word proof as in proof of life or proof
[02:47] of, you know, some scientific proof? And I thought, I'm in over my head, I need to go
[02:54] to my friends to give Mike the appropriate answer, I need to go to the under beatables,
[03:00] and figure out the right answer. So are is the word proof connected to all these things?
[03:06] Are they all related? What is what is my theory on alcohol proof? Is that correct? What is
[03:14] proofing bread even mean? What do we got on proof?
[03:20] One thing I never understood was yeah, you're right. The proof in is the it's just it's
[03:26] always exactly you know, it's just double the it's double the ABB alcohol. Yeah. Why
[03:31] I never understood like, why since it's a it's a it's always double why even bother? Right? Why
[03:37] even bother having this is like, all right, you just take this and then double it. And that's the
[03:41] number. Like, what's the point of that? So I do have a suspicion on this. Okay. For the alcohol
[03:47] ABB verse proof thing. Probably, in the early days of brewing alcohol, what you did was just
[03:55] make grain alcohol, and then cut it was right. Right. So that gets you. That's your ABB though,
[04:03] right? So you're cutting your grain alcohol. Well, so but you always start from 100%. Right?
[04:09] You're like making grain alcohol, and then you're cutting it with something, right? So how much of
[04:15] that cutting you do gives you a proof. Right, which is actually technically a mathematical
[04:22] formula for whatever that's worth. I don't know if those two things are related. But like,
[04:26] if you always start with grain alcohol, which is 100% alcohol, and you pour in some other medium,
[04:34] you end up with, you know, somewhere between zero and 100 or something slightly above zero
[04:42] and something slightly below 100. Right? So that gives you the proof. Right. So okay, so if
[04:47] you're making a liqueur, right, those things tend to be lower proof. Just because there's that alone
[04:57] for let's leave liqueurs a lot. Well, no, no, no, but you're starting with grain alcohol, you put in
[05:01] 50% water, right? Now you're at 50%. Right. You're at 100. Right. You're one to one. Right.
[05:08] But but what's the point of the proof? If I know that I'm one to one, if I know that I'm
[05:14] 50% alcohol, why do I need 100 proof? Well, like I said, my early guess here is that just you
[05:22] started with grain alcohol. So the answer to this question was to what percent is this just
[05:28] pure grain alcohol, because 100% grain alcohol would just kill you dead. Right. So you can't
[05:36] drink. Yeah, so it'll, it'll mess you up. Good. No, ever clear is 120 proof. I believe or 110.
[05:46] I mean, yeah, like 150. You can even do like. So yeah, I think you can even do like 190 stuff,
[05:54] like you can get up there. But like, if you're pure grain alcohol, that stuff is like
[05:59] boarding on deadly real fast. So getting get into pop a Coalson's thing about the proving drawer,
[06:06] and I wonder if these two things are related. The the proving of bread comes from the use
[06:16] of active yeast. And the idea was that you you mix your dough and you mix in your yeast,
[06:23] and then you set it aside, and you allow it to prove, meaning that it will rise because
[06:30] the yeast is doing work. I like that. And it's spitting out carbon dioxide. It will literally
[06:36] it will grow and it will prove to you that the yeast is working. It's working. Right. Yeah. And
[06:40] so I wonder if similar to that early brewing methods were not distilling methods, but rather
[06:52] were fermentation methods like wine and beer, beer, right with yeast and other bacteria or whatever.
[07:02] And the it getting alcoholic is proof that the the yeast or the bacteria or whatever doing their
[07:12] job and fermenting the sugars that are that are there. Right. Yeah. How how it came to be a scale
[07:20] of exactly double baby be like I have no idea. But my only thing with that is that the second you
[07:26] take the cap off the bottle on a fermentation process, you're pretty much done. Like there's
[07:31] no way to prove that. Is there? I mean, well, then like, do you figure out specific gravity,
[07:40] right? Which is how they figure out ABV. Yeah, that's not how we did in Kentucky in the 1920s.
[07:47] Well, I can, you can definitely prove if something's over 100 proof by lighting on fire.
[07:55] Right. Again, once you've uncorked it, right? But how do you prove it during the fermentation
[07:59] process? Right. Right. You don't think they took like little samples and I just I mean,
[08:06] we know what the line is 17 percent alcohol or a beer is, you know, eight point five versus four
[08:13] point three. Like we know that the percentage of alcohol. Right. Yeah. I mean, it's fairly easy
[08:20] once you have it in a, you know, in a once you can put it in a Bunsen burner, you can you can
[08:27] figure it out. Right. But like my problem is like why you've got it corked while it's actually doing
[08:32] its work. I yes, I absolutely question those people's abilities to slip through a syringe,
[08:40] take out a sample, test that. But I think you have to keep it completely airtight. I think you
[08:46] could you could expose it to air briefly. Isn't that what I mean? It's still going to be anaerobic
[08:53] oxidation. I don't know. I don't know the answer to that. I don't know how much that messes up the
[08:58] process. I mean, I'm sure it briefly slows it down because because they would rather use oxygen as a
[09:04] fuel than whatever else it is. But yeah, I don't know. But so anyway, my connection was yeah,
[09:15] that maybe it's a proof thing. The other idea that I had is maybe proof came around to skirt
[09:22] alcohol laws or something like that. So that it was just sort of a code that that's good.
[09:29] Rum runners might use that's like, yeah, yeah, I got this, you know, 80 proof, you know,
[09:38] cola over here or whatever. And and that would be code to people that knew what was going on.
[09:43] So I will say that like whenever I hear proof, the first thing I think of is like a math
[09:49] problem, right? Okay. Yeah. So do these things derive from math?
[09:56] Well, yeah, that's like a primary question. I mean, everything is described by math.
[10:03] Do we at least in this multiverse, do we decide to prove bread or get the proof of alcohol from a
[10:13] term that was previous to that which is coming out of math? Or is it the other way around?
[10:17] I mean, as soon as the like proof is probably some Latin word that means
[10:23] show me the proof. Yeah, prove right. So like, you prove you're proving that the yeast is working,
[10:32] you're proving the fermentation is working, you're proving the math, like,
[10:36] they're probably all related terms because they all like etymologically all come from the same
[10:42] place. Sure. But I don't know if that actually answers the specific question about alcohol.
[10:52] But so we think the reason it's the reason it's double is just like,
[10:56] potentially, it's like, is a code to anti bootlegging thing.
[11:01] I mean, that's one theory could definitely be as Coalson and Harper suggested just a
[11:08] easy formula or whatever to
[11:09] Yeah, you're doubling the alcohol by volume. It's I again, I think it's compared to
[11:17] like water, right? Like if there's if it's 40% ABV, it's 80% alcohol.
[11:25] If you compared that thing to water, right? I don't know. You sound saying that makes sense?
[11:30] Well, no, I don't. I mean, my idea was basically you have two mediums and you're combining them,
[11:35] right? So you basically you start with 200%, right? You've got grain and medium
[11:41] call what call a water, right? And so when you combine them, you end up with
[11:48] whatever X percentage of 200%. And that gives you proof. Like that's where
[11:52] Okay, that's what I feel. I feel like you could just do it as easily without,
[11:56] you know, right, you could do it without the but it sounds more batter ass.
[12:01] Yes. It's gonna sell better.
[12:06] All right. All right. All right. So we were kind of close. Okay, so the term proof dates back to
[12:13] 16th century England when spirits were taxed at different rates, depending on their alcohol
[12:18] content. Some of the terminology and methodology spread to other nations, blah, blah, blah.
[12:25] In England, spirits were originally tested with the basic burn or no burn test.
[12:31] In which alcohol that would ignite was said to be above proof and alcohol which was
[12:40] not which would not burn was said to be under proof. The breakpoint
[12:44] was defined as 100. And was the basis for taxation. Okay,
[12:49] doesn't make sense because we like that stuff on fire.
[12:53] No, this makes no sense at all. Let me just stop right here. Okay, so
[12:58] they decided that they were taxing stuff that burned as opposed to stuff that didn't burn at
[13:06] different levels. Yeah, you just tax it differently. Okay, and I mean, I get I kind of get that part
[13:15] because they're metric people. Right. Well, sort of. Right. And interestingly, alcohol's flammability
[13:23] is highly dependent on temperature. Thus, a hundred proof could range anywhere from 40
[13:30] to 90% ABV in normal air temperatures. Okay. Okay, I can see an 80% at 22 degrees,
[13:39] which is basically room temp 100 proof would be 60 ABV, 60% ABV.
[13:45] Talking Celsius, obviously. So it was not until 1816 that a legal standard based on specific
[13:59] density, which is the way you actually measure alcohol percent by volume, was defined in England,
[14:06] 100 proof was defined as a spirit with 12 13th the specific gravity of pure water at the same
[14:13] temperature. From the 19th century until January 1 1980, the UK officially measured alcohol content
[14:21] by proof spirit, defined as spirit with a gravity of 12 13th that of water and equivalent to 57.15
[14:32] ABV. So it's not exactly double, but maybe the United States.
[14:38] Let's see. Oh, yeah, it's definitely double in the United States. That's, I promise that.
[14:44] I love how this came down to specific gravity. I was like, these are a bunch of dudes making
[14:50] prohibition stuff, but nope, specific gravity. Yeah. And then in the US, it just looks like they
[14:56] were like, uh, let's just, um, let's just double that. Yeah. So it says the term was
[15:01] originally used in England and was equal to 1.8 to one times the alcohol by volume in the
[15:07] United States. Alcohol proof is defined as twice the percentage of ABV. Yeah. We're like,
[15:12] that sounds hard. That's too much math. And, and everybody else, uh, just uses ABV now.
[15:21] Like proof is just, we're the only country in this rockiness right now. Canada doesn't use it
[15:26] anymore. Yeah. Uh, according to Wikipedia, I'll buy it. I mean, I'm sure that look like, so in
[15:35] the States, I'm sure you have to print the percent of alcohol. Yes. Yeah. So in a sense,
[15:44] it's, it's, yeah, you have to prove that it's alcoholic enough to burn. Now, do we know if
[15:51] that's related to proof? Well, okay. So here we go. So I've got proof is from the Latin pro bear
[15:57] to prove, um, meaning act of proving is early 14th century. Meaning act of testing or making
[16:09] trial of anything is from the late 14th century. Um, meaning standard of strength or distill
[16:16] liquor is from 1705. According to at monline.com on some level, like once, once you, once you say
[16:28] the word specific gravity, it's almost certainly from the same place, right? Like, yeah. Adjectable
[16:36] sense proof against is recorded in the 1590s, uh, extended senses involving tested powers such
[16:43] as fireproof, waterproof and foolproof. Um, and then Shakespeare, uh, came up with shame proof.
[16:52] How do you become shame proof? If you just, if you just jackass for long enough,
[16:58] you'll eventually shed what was formerly known as shame.
[17:04] The emotion formerly known as shame. That's correct. Now it's just a
[17:07] glyph that I had tattooed on my face. Well, I'm going to say that we won. I mean,
[17:19] that much is clear. Yeah, this is no game five. It says that, um,
[17:29] proofing bread comes from the old French provere, which comes from the Latin pro bear. Um,
[17:37] dude, that Latin was tight, by the way, your pronunciation was excellent.
[17:44] Was the, you were there.
[17:49] Italian pro barre from probis worthy, good, upright and virtuous. Just saying.
[17:55] I want to give a shout out to my wife. She made bread today and it was awesome.
[17:58] Dude. Homemade bread. It's like a special, special thing. It's real good.
[18:03] Oh, shout out and happy birthday. Catherine, did we shut that out?
[18:09] I don't think we did bad on me. Happy birthday, Catherine. I missed this.
[18:14] I was leaving the window for her husband to do it. Well,
[18:20] the thing is though, like, she's going to hear the same, whether we
[18:25] shout out to the show, you know, give the shadow on the show or not. So yeah, exactly.
[18:30] Coalson, are you, are you satisfied? I am. I don't know why. Um, if, if, if the yeast in the bread and
[18:41] the, you know, the fermentation of alcohol is directly connected and I can't seem to find
[18:47] anything. Um, but I think we're just going to assume that, right?
[18:54] I mean, I think that the same terminology, I mean, it's just this, the concept is the same.
[19:00] I agree. It proved to me that this is what it is. Yeah. Yeah. Yeah. Okay.
[19:05] We're literally undergoing a scientific, a scientific test in both circumstances.
[19:11] Yep. Fair enough. And, and those things can go awry, right?
[19:19] Was that a bread joke? Well, the bread can go awry.
[19:23] Actually, they both can go awry for sure.
[19:27] Rye whiskey. Yeah. So nailed it. Nailed it. Yeah. Chop the mic on that one. Nice work.