DME/LME conversion

So, Im new to brewing. I’ve brewed 2 kits (NB Irish and NB Bavarian Hefe) and as both kits have turned out well, I’m feeling comfortable enough with brewing to give striking out myself a go. I’ve been reading and re-reading John Palmer’s “How to Brew” and as math is far from my strongest subject, I’m having trouble with the DME vs LME conversion equation. I understand the AAU formula but I am stumped with the whole points per pound/ per gallon thing. As I understand it, if a beer is meant to have an OG of 1.045 thats 225 points and if I divide that by 36, I end up with 6.25 pounds of LME. Also, Im assuming this is an equation for a 5 gallon batch. Can anyone tell me if I’m close or even on the right track?? As always, any and all input is greatly appreciated. :?:

Math is my worst subject and i doubt i will help you and i dont think i understand your question…but 1 lb of LME in 1 gallon of water will be an OG of about 1.035…and 1 lb of DME per gallon will yeild an og of about 1.045…To achieve the same OG using DME use 20% less then you would LME.

I think you have your math right, assuming you are talking about a LME that has a 1.036 ppg.

1.045 target OG

(1.045 - 1) * 1000] = 45 points per gallon
45 points * 5 gallons = 225 points per five gallons

Assuming you are using something like NB Amber Syrup (which has a 1.036 ppg), you work backwards:

1.036 ppg - 1 * 1000 = 36 points per gallon

225 points per five gallons / 36 points per pound per gallon = 6.25 pounds

… which puts you right on the money. This, of course, assumes you are still trying to make a five gallon batch. If you are going to increase or decrease the batch, you would change the 6.25 by the ratio of change (if you are going to a 10 gallon batch, you double the 6.25, if you are going to a 2.5 gallon batch, you cut it in half).

One thing that sticks out: I cannot for the life of me think of where AAU (alpha acid units) comes into play in a malt formula – do you have a link or a citation? I may be missing something there.

Cheers.

[quote=“mattbrew83”]
Math is my worst subject and i doubt i will help you and i dont think i understand your question…but 1 lb of LME in 1 gallon of water will be an OG of about 1.035…and 1 lb of DME per gallon will yeild an og of about 1.045…To achieve the same OG using DME use 20% less then you would LME.[/quote]

This is just a rule of thumb based on the idea that extracts are typically 20% water.

Arnold points out that typically LME range between 1.034 - 38 ppg and DME’s range between 1.040 - 43 ppg. At the extreme end (1.034 ppg LME and 1.043ppg DME), that’s a 26% shift. At the narrow end, it’s a 5% shift.

If you have the ppg statistics, use those.

Cheers.