Didn't hit estimated OG.

I just finished my first All Grain batch and according to Beersmith2 I should have had an OG of 1.051, but my reading came out to 1.036.  What would cause it to come out so far off target?  I am pretty sure it won't effect anything in the end (well I hope it won't anyway), but any help here from some veterans would be much appreciated.  Thanks in advance, Cheers!

Greetings Rocky - a number of things can cause you to miss the OG, but the most common cause is the equipment profile in BS, particularly the brewhouse effeciancy, is incorrect and needs to be adjusted to your actual brewhouse efficiency.

I'm not sure how much you have used BS2, but the Profiles that are written are, more or less, templates for the brewer to adjust for their own use.

Another common problem is the milling of the grain.  If the mill is set too wide the grain won't get properly milled and the resulting efficiency gets shot.

Another common problem with all grain brewing is the pH of the mash.  The mash should be between 5.2 and 5.7 pH. If it's outside these parameters, you won't get the proper starch conversion.

Lastly, temperature is also critical for proper conversion.  Most base barley malts today are well modified so a mash temperature of 1530should work well providing you don't have a lot of flaked and unmalted grain in your grain bill.

Hope this information helps or at least gives you somewhere to look.

Good luck!

One other thing to look at is your volumes.  Gravity alone does not give you a good comparison.  If I have a target of 1.050 gravity for a 5 gallon batch, but end up with 6 gallons at a gravity of 1.042, then I have the same brewhouse efficiency, but grossly different gravity due strictly to the difference in ending volumes.

Thanks for the help Keller.  That being said do you have any useful tips on how I can find what my brewhouse efficiency is?  I know I can Google it and I will, but thought I would ask.

Greetings Rocky - unfortunately your actual brewhouse efficiency can't be found on-line or from the manufacturer of your equipment.  Sure, you can get close, but to actually dial in your efficiency will take time and several brews and, as I mention before, pH and water temperature play a huge roll. Plus, as Oginme said, water volumes are equally as huge in the equation.

All that said, my area of expertise lies in the mechanics and construction.  Oginme, on the other hand, helped me (unknowing while helping another brewer) dial in my brewhouse efficiency.  Now I hit my mark every time.  I think he would be able to give you better advice on this subject.

Rocky,

Brew House Efficiency (BHE) is a measure of the amount of sugars from the grain bill which eventually made it to the fermentor.  If you accurately record the measurements for a recipe in your 'sessions' tab for a recipe, then BeerSmith will give you an actual number versus the target number the recipe called for.  I have attached a screenshot with the comparison on the 'session' tab that I had brewed.

Basically, if you are looking for the calculation it goes something like this:

If I took a 12 lb grain bill at a potential of 1.038, I have added 456 points of sugar into my system [ 12 lbs x 38 points/lb = 546 points]

Now if I put 5 gallons of wort into the fermentor at a gravity of 1.060, I have 5 x 60 = 300 points of sugar in the fermentor.

The BHE is the percentage of that initial charge of sugars so it would be:  300 / 456 = 65.8%