What to do if you miss your Original Gravity numbers
We've all done it. You forget something, miss a calculation, or your efficiency is off. Whatever the reason, rather than just accepting what you've got, here are two easy ways to correct a high or low missed OG.
Once you’ve missed your OG you are faced with the problem of what to do with your batch. Fortunately it is not hard to adjust the OG of wort as it goes into the fermenter by using some water or some dry malt extract. Keeping a couple of pounds of light DME on hand can help in a pinch.
If your gravity is too low, add DME using the following calculation:
- Figure out the difference between your target and actual OG, then multiply by 1000. For example, if your target is 1.056, but you've got 1.048 this would give us (1.056-1.048) x 1000 = 8 points. Be sure to temp correct if needed.
- We need to raise our gravity by 8 points which means we need to add 8 points/gallon of dry malt extract (DME) equivalent. Assuming a 5 gallon batch size, we need a total of 40 points of DME.
- DME has a potential of 1.046 which means it contributes 46 points/lb added, so we simply take the 40 points and divide it by 46 to get 0.9 lbs of DME to add.
If the gravity is too high, dilute it by adding boiled or sterile water:
- This time we’ll assume our target was 1.056 but we overshot and came in with a gravity of 1.064, again using a 5 gallon batch. We’ll use the fact that the number of points times volume should be a constant to do the dilution.
- So we start by taking our starting points of 1.064 = 64 gravity points, and multiplying by our original volume of 5 gallons: 64×5 = 320 points
- Now we divide by our target points which is 1.056 = 56 points which will give us the target volume: 320 / 56 = 5.71 gallons
- Since we started with 5 gallons, we need to add 0.71 gallons of water to dilute our gravity to achieve the target of 1.056
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