New Giveaway - Wort Monster Conical Fermenter!

Home Brew Forums > Home Brewing Beer > All Grain & Partial Mash Brewing > Calculating how much extract to use in a partial mash - Does this look right?




Reply
 
LinkBack Thread Tools Display Modes
Old 07-05-2007, 10:04 PM   #1
kenche
Feedback Score: 0 reviews
Recipes 
 
Join Date: Apr 2007
Location: Vancouver, B.C.
Posts: 311
Liked 1 Times on 1 Posts

Default Calculating how much extract to use in a partial mash - Does this look right?

I have been having trouble hitting my target gravities in my partial mashes so have decided to use some simple math to help me out (my teachers were right, math is useful).

Does the following seem right? Is there a simpler formula?

My partial mash yields ~3 gallons of wort. So If I were to take a gravity reading and divide it by two, I would have an accurate measurement of the partial mashes contribution to the total gravity, or is it not so simple?

To then calculate how much extract I need to add, I would subtract that number from my target gravity to determine how many gravity points are missing (the points that the extract would need to contribute)

As Liquid Malt Extract will make a wort of ~1.034 specific gravity per pound of extract per gallon of water, I would then divide the missing gravity points by 34, and multiply by 6 (the batch size) to find out how many pounds of extract to use.



__________________
kenche is offline
 
Reply With Quote Quick reply to this message
Old 07-05-2007, 10:49 PM   #2
Rook
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Rook's Avatar
Recipes 
 
Join Date: Jan 2007
Location: Bothell, WA
Posts: 381
Liked 1 Times on 1 Posts

Default

Download beersmith. I've found its fantastic for converting AG to PM recipies, or extract to PM.

You put in the recipe that you have to start from, then subtract extract and add base grain (or add extract and subtract base grain) to achieve the desired result.

Plus you get to keep a nifty collection of your recipes.



__________________
Rook
Rook is offline
 
Reply With Quote Quick reply to this message
Old 07-05-2007, 11:44 PM   #3
david_42
Feedback Score: 0 reviews
 
david_42's Avatar
Recipes 
 
Join Date: Oct 2005
Location: Willamina & Oak Grove, Oregon, USA
Posts: 25,650
Liked 130 Times on 124 Posts

Default

Your method works.

__________________

Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"

"I would like to die on Mars, just not on impact." Elon Musk

david_42 is offline
 
Reply With Quote Quick reply to this message
Old 07-06-2007, 12:33 AM   #4
Warped04
I am Wally
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Warped04's Avatar
Recipes 
 
Join Date: Jul 2007
Location: San Diego, CA
Posts: 1,458
Liked 3 Times on 3 Posts
Likes Given: 2

Default

Quote:
Originally Posted by Rook
Download beersmith. I've found its fantastic for converting AG to PM recipies, or extract to PM.

You put in the recipe that you have to start from, then subtract extract and add base grain (or add extract and subtract base grain) to achieve the desired result.

Plus you get to keep a nifty collection of your recipes.
We are looking to do it mid brew. So we do our PM and as it enters the boil kettle take the Gravity, then figure out how much extract we need to add to hit our desired gravity.
__________________
Warped04 is offline
 
Reply With Quote Quick reply to this message
Old 07-06-2007, 03:23 AM   #5
kenche
Feedback Score: 0 reviews
Recipes 
 
Join Date: Apr 2007
Location: Vancouver, B.C.
Posts: 311
Liked 1 Times on 1 Posts

Default

I think it will work, also it is worth mentioning that Dry Extract contributes more gravity points than liquid.

DME will make a wort of ~1.045 specific gravity per pound of extract per gallon of water. Therefore you would need to divide the missing gravity points by 45, and multiply by 6 (the batch size) to find out how many pounds of extract to use.

I will try this technique next brew.



__________________
kenche is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Calculating efficiency in a partial mash petep1980 All Grain & Partial Mash Brewing 3 10-05-2009 08:54 PM
partial boil/partial mash+ late extract addition undallas All Grain & Partial Mash Brewing 4 02-10-2009 01:08 AM
Partial Mash - Calculating Efficiency JMD87 All Grain & Partial Mash Brewing 8 05-29-2008 07:14 PM
My Extract vs. Partial Mash Limited Visibility General Techniques 3 05-05-2008 11:28 AM
Calculating total runoff for partial mash? cweston All Grain & Partial Mash Brewing 1 03-15-2006 01:56 AM