OG is nearly always high

I seem to always run high in my OG and I am not sure what to tweak to try and fix that. My pre-boil readings are pretty good but after a typical 60 minute boil I always end up high. My last batch was estimated at 1056 and ended up 1060 and if all else goes as planned the ABV will be 6.6% instead of 5.6%. Any idea on a good place to start?

OG is a function of "gravity units" for a given amount of wort.  If you ended up with an OG of 1.060 with (for example) 5 gallons of wort, that would be equal to 300 gravity units (60 * 5). Had you started with 6.5 gal at a pre-boil gravity of 1.046 (6.5 * 46 = ~300), and boiled down to 5 gal, you would get 1.060 OG.  Had you boiled down to 5.5 gal, your OG would be 1.054 (5.5 * 54 = ~300).  So, you could either boil for a shorter period and have more wort, or you could adjust your OG at the end of the boil by adding more (sterile) water to lower your OG.

OK, let me rephrase the question. How can I tweak BS2 so that I am closer to the OG that BS2 predicts without shortening the boil or adding water?

To me, a major reason for BS2 is to have the tool do much of the work for you so that you can get consistent results. That entails things like how much water for mash and sparge given all the parameters you input. I was hoping for ideas on what to tweak in BS2 so that the OG numbers are closer to the expected results.

Since you have good pre-boil readings the only other thing that could be happening is high evaporation during the boil. You can adjust this in the equipment adjustment section of the software. That being said 1.06 to 1.05 is pretty far off - just a quick calculation says you are almost a gallon of water off! What are you using to measure gravity? What temperature is the wort when you measure gravity?

Mike

Measure pre boil volume. Measure, don't guess. Measure post boil. If needed, adjust evaporation rate.
Check temp when reading gravity, and correct.
If you check at preboil and the gravity is where you want it, the only way it can raise is to remove water (evaporation). If you don't correct for temp, your reading will be off.
Do you add DME? you didn't say.
I had the same problem, so I measured water in kettle, boiled 1 hour, and measured again. I adjusted my evaporation rate to match, and solved the problem.

I agree. The only thing that I could add is to check if your hydrometer is calibrated.

mbg-bs said:

Since you have good pre-boil readings the only other thing that could be happening is high evaporation during the boil. You can adjust this in the equipment adjustment section of the software. That being said 1.06 to 1.05 is pretty far off - just a quick calculation says you are almost a gallon of water off! What are you using to measure gravity? What temperature is the wort when you measure gravity?

Mike

Click to expand...

I'm glad you asked me that. I am using a TC refractometer for the pre-boil measurement. I take a small sample with a tiny bowl and cool it quickly by putting the the bowl into a larger bowl with ice cubes. I have calibrated the refractometer a few times in the past but I could do it again. I did also check it against my cheap hydrometer. I haven't checked the actual temperature when measuring but I could start to do that. When I have checked both my refractometer and hyrdometer against each other they have been in sync so if there is a problem with my measurement it is found in both tools I use (I admit it could be possible).

Any conclusion is only as accurate as it's least accurate measurement.
If temperature is unknown, all conclusions based on that will be unknown.
Measure volume and temperature, don't guess. This is an easy and cheap way to improve your batches.

Prosit.

One other thing to check is your brewhouse efficiency.  I used the default until I saw a similar issue, higher OG.  Then I calced my efficiency and now things are nearly always spot on.