# What factors go into calculating perceived sweetness/bitterness?

Some sites calculate bitterness vs sweetness on a scale of sorts, where one side is "malty sweet", and the other side is "hoppy bitter" (ex. hopville).

My question is, to do a very basic calculation of this, what factors are involved?

Could you determine this by simply knowing the ABV and IBU of a beer? Or would you need to also know the specific gravity?

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Some interesting things I came across: thescrewybrewer.com/p/brewing-tools-formulas.html#bbc and an article referenced in that link about balance web.archive.org/web/20100507203942/http://… (retrieved via the wayback machine). I was typing up an answer, but wasn't sure enough I was getting things right to post it. So, figured I'd at least leave the links here for others to review. –  fire.eagle Oct 30 '12 at 18:36
Very helpful. In these equations, you need to know the specific gravity of the beer. In your opinion, do you think it would be possible to estimate gravity units by simply knowing the ABV? –  JasonStoltz Oct 31 '12 at 9:34
You should be able to get a guess. If you know the recipe, you should be able to get the OG from that, then use that in the formulas you got in your question about FG from OG and ABV. If not, you should be able to set up an equation with the attenuation formula, then solve that along with the ABV equation to get an estimate. Not sure, but that sounds about right to me right now. I'll leave setting it up as an exercise for the reader. :P –  fire.eagle Oct 31 '12 at 13:43

There is no calculation for sweetness. There are no sweetness units. Whenever I have seen this type of "grading" that you describe sweetness is just some sort of arbitrary lack of bitterness. But there is no reciprocal type calculation.

Taking it a step further how do you calculate something that has the qualifier "perceived" in the title. Perceived sweetness is variable person to person and not a concrete quantifiable character of beer.

The closest thing you have to what you are looking for is GU:BU ratio described by Ray Daniels in Designing Great Beers.

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In your opinion, do you think it would be possible to estimate gravity units by simply knowing the ABV? –  JasonStoltz Oct 31 '12 at 9:34
I mentioned hopville in my post. It looks like they actually are using "BU:GU". –  JasonStoltz Oct 31 '12 at 10:14

Just going to throw this in a well.

I agree perceived is hard to really calculate from person to person. It is simply that the more non-fermentable dextrines that are in your wort, the perceived bitterness will be lower. 80IBUs suddenly tastes like 20-30IBUs. Same goes for the other side, if the beer is dry and hoppy. 80IBUs may seem like 110IBUs.

This happens a lot in BJCP competitions. While the minimum IBUs for a IIPA is 60IBUs, no one is going to get a good score with that low of IBUs on a IIPA. This is simply because the IBUs are not pronounced enough for the other guidelines in the IIPA category.

So now that that is out of the way, let me talk about your actual question.

If I take 45lbs of grain: 40lbs of 2 row, 2lbs carapils, 3lbs belgian candied sugar for a 5 gallon, mash at 144^dF for 1.5 hours. Boil 90min and add 2oz Cascade at 90min. Ferment slightly colder than suggested on a Ultra High Gravity yeast. Now I have a 17% barley wine with maybe 20IBUs that is going to be bone dry.

Now I take the same beer: 45lbs of grain: 40lbs of 2 row, 2lbs carapils, 3lbs belgian candied sugar for a 5 gallon, mash at 154^dF for 1.5 hours. Boil 90min and add 2oz Cascade at 90min. Ferment at suggested temp on a Ultra High Gravity yeast. Now I have a 17% barley wine with maybe 20IBUs that is going to be a malt bomb.

So you need to know a few things to figure out which side of malt or hop bomb you are going to get. Of course, that second beer with 20IBUs is not even going to taste like hops are in it and the first will have a little more of the bitterness.

Hope that helps!

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