Following on my first post about my Easy ABVs application for the iPhone, I’ve now completed the application and thought I’d post a few pictures and describe how it works. Easy ABVs is a calculator application specifically designed to calculate alcohol content of a spirit, and show how adding water affects the final ABV (Alcohol by Volume). In addition to cleaning up the appearance, I’ve made pretty much all of the settings user-configurable, and added an information screen. I got around my lack of artistic abilities by going with a completely text-based application icon. It’s supposed to be a take on a grade school “ABCs” notebook ledger.
The calculator (Final ABV mode)
The calculator allows you to enter the original ABV of a spirit, the size of the drink you’re pouring, and by default, the amount of water you want to add. Note the combination of text boxes and sliders. I find the sliders to offer a level of convenience that you don’t get with similar web-based calculators. For one, I can enter the data a lot faster with the slider. Another benefit is the ability to progress through a bunch of numbers and see real-time updates in the results pane.
The results pane (panel at the top) displays a number of relevant calculations:
- Pure Alcohol = Spirit Volume * (Spirit ABV / 100)
- Drink Units takes the amount of pure alcohol and divides it by the number of ml considered to make up a single “drink unit.” There are standard drink unit sizes for the UK and US. More on that further down.
- Total Volume = Spirit Volume + Water Added
- Final ABV is the Alcohol by Volume for the combined water and spirit.
The calculator (Add Water mode)
The above image shows the calculator after I clicked the “swap” button right below the results pane. Now, instead of entering an amount of water to add and seeing the calculated Final ABV, you enter a Final ABV and see the calculated Add Water amount in order to dilute the spirit to the desired strength. This can be handy if you’re comparing a number of whiskies and want to try them all at the same strength. Simply set the Final ABV where you want it, and adjust the Spirit ABV for each whisky. The calculator will show you how much water to add.
The settings tab
Pretty much everything in the calculator is user-configurable. You can set the min/max values for the sliders. I recommend setting them so that the range is as small as possible, based on your normal use. This way you can be more accurate with the sliders. The more numbers, the more difficult to land on a particular one. The default values are also configurable. These are the values for when the application starts up, and when you hit the reset button. I’ll discuss the Drink Unit size in the next section.
The information screen
Clicking the “i” button in the lower right corner of the settings screen causes the screen to flip over and reveal some information about the whole Drink Units concept. The UK and US have similar guidelines for what they consider “moderate” drinking. They use different base drink sizes, but recommend similar total limits on a daily/weekly basis. The 10 ml drink unit in the UK is based off of a 25 ml serving of a 40% ABV spirit. The ~17.6 ml drink unit in the US is based on the amount of alcohol in a 1.5 oz shot of a 40% ABV spirit. I’ve set the default drink unit size to the UK 10 ml, but of course, it’s fully configurable. You could even come up with your own drink unit size based on your own habits/preferences.
I’m going to try posting this to the iTunes App Store and see what the process is like. I’m not charging anything for this application. I figure the potential audience is fairly small. You need to not only be into drinking spirits, but you probably need to be something of a geek. :-)
So…any whisky geeks out there want to give this a try before I post to the App Store and give me feedback, or see if you can break it?