SRM/Lovibond question

Why are Crystal/Caramel malts rated 10-160 not as dark as beer at those ratings? I've read it's the ground up color of the malt, but a 40L/52SRM beer is jet black, 40L crystal malt is a reddish/tan color, is this just a liquid vs. solid thing?

fizgig said:

Why are Crystal/Caramel malts rated 10-160 not as dark as beer at those ratings? I've read it's the ground up color of the malt, but a 40L/52SRM beer is jet black, 40L crystal malt is a reddish/tan color, is this just a liquid vs. solid thing?

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Beer is color rated using SRM, while grains are color rated using Lovibond. This site lists the various formulas to covert between the two. http://homebrew.stackexchange.com/questions/2632/how-do-you-convert-between-srm-and-lovibond

Agreed, but Lovibond and SRM are not that far from each other.

I was curious so I looked at this in Matlab.

If we define MCU (malt color units) as the weight of the grain times the color (in deg. Lovibond) divided by the volume, then the SRM is 1.4922*MCU^0.6859 (as per Daniels).

Looking at these two plotted side by side, generally speaking, MCU over estimates the color of the beer as it gets darker. The two scales are within 1 point until the MCU hits 6.25 (5.25 SRM). From there it diverges significantly, an MCU of 20 corresponds to an SRM of 11.65.


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Hmm thanks for that info, I looked it up, it doesn't explain like a crystal 80 or 120 which should still be black:

The Morey Equation

While MCU is a good estimate for SRM beer colors < 10.5, the MCU color overestimates the color value for darker beers. In an article on Brewing Techniques Dan Morey proposes using a slightly more complex equation based earlier work and raw data by Mosher and Daniels to handle darker beers. This equation holds for values of SRM up to 50. Most beer software uses the Morey equation. The Morey equation is derived from the MCU value calculated above.
SRM_Color = 1.4922 * [MCU ^ 0.6859] -- Good for beer colors < 50 SRM

I think I might have found a partial answer, it's a pounds/gallon of water rating of the wort and not the color of the malt itself:

A rule sometimes used by homebrewers is that the color contributed by a malt is equal to its concentration in pounds per gallon times its color rating in degL. For pale beers this rule can give reasonable results. For example, 10 pounds of pale malt with color 1.6 degL in five gallons should produce a beer whose color is near 1.6 x 10/5 = 3.2degL.

However, putting 6lbs of crystal 80 in a 5 gallon batch gives me a color of 32.9 in beersmith, so that can't be right either.

It depends on the transmission distance (i.e. path) used in the spectrophotometer reading.

A carboy of dark stout will allow less light through than the same stout in a 16 oz glass which in turn will let less light through than the same stout in an imaginary glass of 1cm in diameter. Each of those will produce a different color for the same stout.

This phenomenon can be seen in the various SRM diagrams here (1cm path) vs (5cm path) vs (10cm path) (the colors get darker as the path gets longer):

https://www.homebrewtalk.com/f128/calculation-srm-rgb-values-srgb-color-space-413581/#post5257319

As well as the beer colors diagram here:

http://www.pbase.com/agamid/image/118826578

The actual measurement of the color of the grain is done by creating a 1.032 wort using said malt (and perhaps a base grain) and measuring the color using a spectrophotometer using a 1cm path.

Ahh, that makes sense, I never see that mentioned in any of the literature I've read. Is it normally 1cm for the grain rating and 10cm for the beer rating? I assume it's standardized.

It's 1cm for both as the spectrophotometer used to measure the color has a 1cm3 chamber.

There's a difference between the color of raw wort and the color of a fermented beverage.

Dissolve 32 points of sugars from a Crystal 10 malt in distilled water

Now dissolve 32 points of sugars from the same Crystal 10 malt in distilled water and then ferment.

What is the difference that you see?

Well that takes me back to my original question, wouldn't 120L crystal be jet black, the wort certainly is not at 10cm, and fermented it is likely lighter.

fizgig said:

Well that takes me back to my original question, wouldn't 120L crystal be jet black, the wort certainly is not at 10cm, and fermented it is likely lighter.

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fizgig said:

However, putting 6lbs of crystal 80 in a 5 gallon batch gives me a color of 32.9 in beersmith, so that can't be right either.

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32.9 SRM does not equal 32.9 Lovibond.

Color measurements (in these color spaces) don't work like standard or metric measurements (i.e. 1in = 25.4 centimeters). You can't say 10L = 10SRM. There are attempts at conversion using MCU (Malt Color Units) and other esoteric equations (Morey, Daniels, etc...) but these break down at various points along the way.

Color, it's perception and mathematical representation is a complex subject. If you're really interested look up CIE, XYY, XYZ and LAB color space.

There are malts with a "rating" of 400L but we don't say a beer made with that malt has a color of 400 SRM. Most pieces of software use simple lookup tables, clamping the translation from L to SRM to a max of 40 (it get's worse when that software tries to display the color on screen...).

Now if you were to measure beer and malt using the same lovibond scale they would in fact correlate (on that scale). But beer is usually measured using SRM and malt is "rated" using Lovibond.

"Rating" malt by color is perhaps an outdated method, but it's something that can be identified with. You know a crystal malt rated at 10L is sweeter than a crystal malt rated at 120L which has more raisins/toffee. You know that a roast malt rated at 300L is less roasted than a 400L malt.

fizgig said:

Why are Crystal/Caramel malts rated 10-160 not as dark as beer at those ratings?

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Asking this is really asking for an apples to oranges comparison. Using Lovibond for a malt rating comparison may be applicable for communication purposes concerning that malt but not for color comparisons of malt and beer.

Historically they rated beer with Lovibond using colored glass and converted to SRM scale to be instrument based instead of comparing the colors, but the scales were still very close, you are incorrect.

http://beersmith.com/blog/2008/04/29/beer-color-understanding-srm-lovibond-and-ebc/



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fizgig said:

Historically they rated beer with Lovibond using colored glass and converted to SRM scale to be instrument based instead of comparing the colors, but the scales were still very close, I don't think you are correct.

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Comparing the color of malt and the color of beer is like comparing apples to oranges when using different scales. Saying 10L malt doesn't equal a 10L beer doesn't make any sense, they are equal when using the same scale. Saying a 10L malt doesn't equal a 10 SRM beer does make sense because the scales do not correlate perfectly.

You are wrong, the color rating of the malt is determined by the color of the wort made from it, beer can be rated in Lovibond not just SRM.

fizgig said:

You are wrong, the color rating of the malt is determined by the color of the wort made from it, beer can be rated in Lovibond not just SRM.

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Yes, beer color can be Lovibond or SRM, but you can't compare a 400L malt to a 400 SRM beer or a 10 SRM malt to a 10L beer. You could compare an 80L malt to an 80L beer because they use the same scale. 60L is 60L no matter if you are measuring (or rating) wort or beer.

My original post references a 40 lovibond slash 52 SRM beer vs a 40l crystal malt, if you don't know the answer, please stop arguing semantics and posting in this thread, the two scales measure the same thing, you're arguing like you can't covert miles to kilometers or gallons to liters, they both measure color.