[bathtubbrewer]

I bought "How to Brew" a couple days before I bought my first kit.  Since the kit was pretty much just handed to me by the guy at my brew shop, I wanted to do a little work (as described in How to Brew) to make sure I understood what I was doing and why I was doing it.  I started by trying to calculate my OG.  Here's my question/problem:  I don't understand why some malt extracts are measured by 'points' and some are measured by the Lovibond scale.  I was given two 3.3 lb cans of LME Amber (35 points) and a 1 lb bag of Munton's Amber DME with a Lovibond rating of 7.  Is the Munton's just for color?  If so, when do I add it?

I made my first batch anyway...  Couldn't wait any longer.  Wish me luck.

[tygo]

Lovibond is a color scale.  Specific gravity or points per pound per gallon (pppg) are a measure of the sugar contribution.  Amber DME should have around 44 pppg.  So your 6.6lbs of Amber LME and 1 lb of Amber DME should give you a specific gravity of 1.055 assuming it's for a five gallon batch.

6.6lb x 35 pppg = 231 gravity points
1.0lb x 44 pppg =  44 gravity points
Total Gravity Points = 275

Original Gravity = 275 / 5 gallons = 55 points per gallon or SG 1.055.

[tschmidlin]

There are two different things being given to you.  Both forms of extract will have gravity points to contribute, and both will have color (Lovibond scale), even if it's not explicitly told to you.  To calculate your gravity you use the points, to calculate color use the Lovibond number.

For your gravity you've got 6.6 lbs of LME and 1 lb of DME.  The LME is 35 points, which is per pound in a gallon of water.  The DME should be around 44 points.  So you've got 6.6 * 35 + 44 / gallons, or 275/5 (assuming a 5 gallon batch) or 55 points, which translates to a SG of 1.055.

Make sense?

<edit>what tygo said

[bathtubbrewer]

Thanks to you both!