Yesterday, I described how I made some hand sanitizer using the WHO’s recipe. Today, adventures with a Proof and Tralles Hydrometer. Read on for the mixed results.
First, one of note on yesterday’s post. As some of you pointed out, you need to use 3% hydrogen peroxide, not some higher grade stuff – that shit will dissolve your hands, not clean them.
I bought the hydrometer from Amazon for $7. Since the first one didn’t ship on time, I ordered a second one. Both arrived today, of course. This thing is not the world’s most complex or probably accurate instrument, but we’re just looking to make sure that our hand san is in the ballpark of the 75% the WHO recommends for their isopropyl alcohol formula, which is way above the 60% the CDC recommends as the minimum alcohol content.
These things are 11 inches long, and ideally you’d use a graduated cylinder or other tall narrow container for your sample. My kitchen lacks that piece of equipment, and I’m impatient, so I found the biggest, fullest bottle of liquor I have for a rough-and-ready test, some 80 proof (40% alcohol) Brugal Anejo Dominican Rum.
The procedure is to place the hydrometer in the bottle, make sure it isn’t touching the bottom, spin it to get rid of air bubbles, and I found that pushing it in and letting it float up a couple of times would get you to a repeatable reading. This reading is about 39% alcohol. At 68 degrees F, the reading is supposedly ~3% high, according to a correction chart supplied with the hydrometer, so it’s more like 36%. Either Brugal is lying to us when they say their liquor is 40% alcohol, or some alcohol evaporated out, or this thing is a little off. That’s the problem with kitchen chemistry, you can’t fully trust your references. (Both hydrometers read about the same on all samples, by the way.)
The second reference I tried was 70% rubbing alcohol from a bottle I opened two days ago. I used a new Smartwater bottle as the container.
This is around 76%, and with the temperature-based correction factor of 3%, we’re at 72%. The WHO guidance says that a 75% isopropyl solution will read at 77% on this type of instrument (which is made for ethanol), so a further correction factor of ~2% gets us to ~70%, which is what it says on the bottle.
Alright, time for the grand finale. Here’s the hand san.
That’s just a tiny bit above 80, with a correction factor of 3, we’re at ~77%, which the WHO says is what this instrument will read for 75% alcohol, the target for this formulation. So, Yahtzee. This will be ready to use by Tuesday afternoon (after the 72 hour wait). Note that I will let the sample I poured into the Smartwater bottle sit for an additional 72 hours in case I introduced any contaminants.
Final formula for ~5 liters of hand san:
3784 ml 99% Alcohol (8 16 oz bottles)
210 ml 3% Hydrogen Peroxide
73 ml Glycerin USP
1000 ml boiled distilled water
Note that this is ~1.4% glycerin, for those of you who were worried that it would throw off the hydrometer.
Medium Cool with BGinCHI – You’re the Producer
Andrew
Brugal rum likely adds sugar to their rum (many rums do and lie about it). That kind of hydrometer only really works accurately in alcohol/water solutions. Once you add things with different densities it will be less accurate
Kathleen
CoVid-19 but not hand sanitizer related – DeWine is shutting down all bars and restaurants in Ohio. He wants to stop the St Patrick Day crowded bar scene from occurring. Restaurants can still offer carry out. Affected employees can file for unemployment immediately and get benefits without wait period. DeWine is doing a great job here, I believe.
Luciamia
Does alcohol evaporate? I know evaporation of some whiskeys happen in the barrel and are called the “angels share.” But the alcohol alone?
download my app in the app store mistermix
@Luciamia: Yes. That’s why I was careful to seal my storage containers with Saran Wrap and then tightened the caps.
Thrasius
The correct way to test a hydrometer calibration is with distilled water. There are usually gradations for specific gravity on them. So it should read exactly 1.000 at 60 degrees Fahrenheit (or whatever the calibration temperature is).
Source: Beer brewer (me)
debbie
@Kathleen:
It was a very good news conference, but why was his wife there? Why do I get the vibe that she’s a puppetmaster?
I have a niece who waits tables and boy, is she pissed.
different-church-lady
I”M IN CRISIS HERE!
THERE’S NO MORE SWEET VERMOUTH!
I JUST MADE MY LAST MANHATTAN FOR THE NEXT TWO MONTHS!!!1!!
Mnemosyne
@debbie:
Hey, if the puppet master (puppet mistress?) is getting DeWine to take sensible public health steps, I wouldn’t complain. Hopefully they’ll be able to utilize your niece to help with takeout orders so she’s not completely SOL.
Mnemosyne
@different-church-lady:
OH MY GOD! NO! ?
Gin & Tonic
@different-church-lady: There are other cocktails.
joel hanes
@different-church-lady:
pssst.
https://smile.amazon.com/Carpano-Antica-Formula-Vermouth-100cl/dp/B008A1WF72/ref=sr_1_2?crid=1DP1ON4K6THVF
apologies if that’s not the right stuff
download my app in the app store mistermix
@joel hanes: That’s the best stuff….
kevin
Mistermix,
looks to me over the past couple of days like you are just living out your Breaking Bad fantasies these days, except replacing Walter White’s lab poison with life-affirming, upstate chemical concoctions instead.
how are your family members reacting to your new life purpose??
different-church-lady
@Gin & Tonic: GO TO YOUR ROOM!
BruceFromOhio
@different-church-lady: To hell with the vermouth, how’s the supply of bourbon?
BruceFromOhio
@debbie: Our local small-plates place put out a SOS signal not long after the announcement. They had stocked for St. Paddy’s and were looking to shed as much as possible. The place was actually closed, and had just finished a reservations-only beer tasting when the announcement came out. We zipped over for some wines and carrot cake.The mood was the same, wtf, but also wtf are you gonna do about it. The kitchen was shifting to planning a family meal menu for take-out only, which hopefully keeps the place afloat, but kills the business for the wait staff.
Look for a way to file for unemployment is the only option I can think of; I hope her place is still there when the smoke clears.
It’s all like a long swim underwater – if you can hold your breath and make it to the end, you’ll survive, otherwise, probably not. A lot of little places that depend on cash flow to survive are not going to make it.
KrackenJack
The formula published earlier was pretty simple. I’d tend to trust the labeling on the alcohol and the volume math more than a roughly calibrated hydrometer with multiple correction factors. Still it’s an interesting exercise. Definitely thinking more about chemistry and microbiology than I have since college.