OG differences between All Grain and Extract

I am an Extract brewer and it seems like Beer Smith wants me to add lots more extracts to get the OG up to what a recipe from Brewer's Best or John Palmers's book "How to Brew" suggests.  I recently made a recipe from Brewer's Best, followed the directions except did a 3 gal boil rather than 2.5 gal boil and OG came out as planned (1.061).  But Beer Smith 2 for Ipad suggested that my OG would be 10 points lower at 5 gallons.

So I went to Briess Malts website, their datasheet says that 1.36lbs per gallon of Golden Light LME will yield an OG of 1.050. (6.8 lbs @ 5 gals)
http://www.brewingwithbriess.com/Assets/PDFs/Briess_PISB_CBWGoldenLightLME.pdf

So then I enter that data into Beer Smith 2.  With Brew type set to All Grain and 6.8 lbs of Pale Liquid Malt (78% yield) OG = 1.049  pretty close.
Switch brew type to Extract and results = 1.042.

If I change the yield to match the data sheet value of 75% I get:
All grain = 1.047 OG
Extract = 1.041 OG.

I made one batch of beer based on BeerSmiths Extract calculations of OG, and I diluted that 3 gal boil to 5 gallons.  The OG was high, so I diluted it much further to reach the target OG.

It seems like BeerSmith calcs are working for me if I used All Grain brew type but seem low if I use Extract. I have played with trub loss and top off values and that helps, but does not seem to fully address differences.  Why are OG values varying between All Grain and Extract brew type for extract ingredients?
Is the process that Briess is assuming different then the process Beer Smith uses?
I am seeing similar actual values for OG as Briess, and Brewer's Best indicate.

 

I'm not able to duplicate this flaw on the desktop version from your description. I'll follow up with the mobile, in a bit.

Extract recipes with 100% extract should be identical. Make sure that the extract is classified as "extract" in the ingredient profile and not as something else. Fermenter top off should track identically, as well. Beyond that and you have some variables to consider and perhaps adjust.

The main difference between all grain and extract, within BeerSmith, is how it treats the extraction of specialty grains. You don't mention using specialty grains, but I'm fairly certain neither source has recipes without them. In extract, the gravity contribution default is 15% of all grain. You can change the extract number: Options > Advanced > Steeping Efficiency.

Thanks for looking at this. I am familiar with the differences in calculations with steeped grains between BeerSmith and Palmer book.  But the differences I am seeing are greater that what that would impose.  Trying to troubleshoot I went for the basic LME example, with no other ingredient example.

I checked and my "Pale Liquid Extract"  has [Type] = "Extract" and [Yield] = 78%

I get a similar variation for the "Light Dry Extract" grain in BeerSmith 2 for Ipad.  With the brew type set to Extract the OG is much lower than when set to All Grain.

I do not have the desktop version to try it on.

I did some more experimenting.  The gravity stays the same between Extract and All Grain if the Trub loss is set to 0.  I understand that the gravity will be reduced if diluting to a pre-set volume after the boil, as some of the fermentables are lost with trub. I do not understand why trub loss would only lower the gravity of an Extract versus All Grain Beer. 

wepperly said:

I did some more experimenting.  The gravity stays the same between Extract and All Grain if the Trub loss is set to 0.  I understand that the gravity will be reduced if diluting to a pre-set volume after the boil, as some of the fermentables are lost with trub. I do not understand why trub loss would only lower the gravity of an Extract versus All Grain Beer.

Click to expand...

Yeah, I found this too.  Lost to trub/chiller does not work correctly for Extract beers.  I set this to 0 when brewing those.

Mark

I think I am starting to understand BeerSmith.  It uses a different brewing process than I use.  I typically follow a recipe where the crushed caramel grains are steeped in fixed amount of water (2.5 or 3 gallons of water).  Then brought to a boil.  With 2 cans of LME used the volume typically increases to 3 or 3.5 gallons(Boil volume for hop utilization).  Once I pour the wort into the fermenter I measure the gravity and use BeerSmith to calculate how much water to add to hit my target OG.  Add that water, then test OG again and pitch yeast.

For me it would be better to enter how much water is added to the pot as an ingredient, the boil volume is calculated from the ingredients (water and LME), and the top up water is calculated from a target OG, Batch Size,estimated trub loss, and boil loss.  As when I am making modifications to a recipe I have a target OG and IBU levels.

Basing a recipe on Top up water, rather than initial boil water is confusing me.  As I change top up water in the equipment editor the boil volume automatically changes.  To use this it seems like I would need to subtract the LME volume from the software suggested Boil volume to know how much water to add to the pot prior to steep time.  The process is confusing to me.
But I guess it all makes sense now.  If I use 2.5 Gal top up, .5 Gal trub loss, and default cooling and boil losses, my boil volume is 3.66 Gallons.  Which is about right for 2 cans of LME and 3 Gallons of water.  I suspect if I use these values I will end up with a dead even 5 gallon batch every time with the correct OG.  I'll just have to change top up water when less LME is used. 

wepperly said:

I do not understand why trub loss would only lower the gravity of an Extract versus All Grain Beer.

Click to expand...

It has to do with BeerSmith using Brewhouse Efficiency to calculate gravity, rather than merely relying on Mash Efficiency. Brewhouse Efficiency is saying the percent of sugar that makes it into the fermenter based on the total amount available from all sources. In all grain recipes, if that percentage remains constant, then the sugar needed to account for losses must come from increased mash efficiency.

In an extract recipe, the total gravity is calculated differently. It's simply the total extract sugar available, plus steeping grains (15%), divided into the total post boil volume. Brewhouse Efficiency isn't a factor.