BIAB. Preboil gravity way high...

[Scuba_Steve81]

I am mid brew right now. My preboil gravity is suppose to be 1.036. I chilled to 109 to get a semi accurate reading. My gravity was 1.052... That is before temp adjustment too, so it is even higher. What the hell went wrong?

 

[BeardedBrews]

Some options

1. Bad hydrometer reading. Does the hydrometer read 0 in plain water? Are there chunks in the sample? Bubbles? Set the sample aside and test it again later to confirm.

2. Bad recipe calculation. Did you key everything in correctly? Does your recipe calculator have the same pre-boil volume that you see in your kettle?

3. Too much grain. Could you have accidentally weighed out your 2-row twice while you were milling?

4. Too little volume. Related to #2, are you planning to sparge, and if so, is that volume included?

5. MAGIC! You created bonus sugar from nowhere, you are obviously a sorcerer! Rejoice.


Too high is a good problem to have, your beer may not be quite as bitter as planned, but you can always dilute the final wort when you're putting it in the fermentor. Just take that last gravity sample before you add any extra water.

 

[doug293cz]

What was your:

• Grain bill?
• Strike water volume?
• Pre-boil volume?

Did you sparge? Answers will allow sanity checking of your measurement.

Brew on

 

[Scuba_Steve81]

I just thought of this... Maybe the preboil gravity reading on the calc is telling what the gravity should read at mash temp? 154 degrees. I messed with a calc, and to get an equal adjusted gravity at 109 and 154, the 154 would have to be 1.040, which is much closer to my intended gravity. Seem correct?

 

[doug293cz]

I just thought of this... Maybe the preboil gravity reading on the calc is telling what the gravity should read at mash temp? 154 degrees. I messed with a calc, and to get an equal adjusted gravity at 109 and 154, the 154 would have to be 1.040, which is much closer to my intended gravity. Seem correct?

I'm not aware of any calculators that give SG's at elevated temperatures (is anyone else?). I doubt this explains your anomaly.

Brew on

 

[BeardedBrews]

I haven't seen one report elevated temp SG, but that would be a neat feature.

Either way, at this point the boil has to be nearly done. The best bet at this point is going to be to record your volumes as close as you can and keep on moving. Once the wort is chilled and in the bucket (but before you pitch yeast) you can get your final number and make adjustments.

Since the worst case is that you're strong, you don't need to worry about adding DME before the end of the boil.

 

[Ozarks Mountain Brewery]

I get a kick from preboil gravity questions, that reading your comparing to is based on an exact recipe and the equipment settings and water levels it has in it, the problem is theres hundreds of ways to brew that recipe and very few set ups are just alike, the only way to zero in on a preboil gravity is create your own recipe and brew it over and over again to establish your settings, water and losses then change that recipe to meet your system. I know thats a pain but we've all done it at some point

 

[khannon]

Brewers friend has a calculator. hydrometer temp correction included in the Android app... check under calculators.

 

[Scuba_Steve81]

Here are my parameters.

8 oz American - Caramel / Crystal 60L 34 60 4.2%
10 oz American - Victory 34 28 5.3%
4 oz. American - Chocolate. 29 350 2.1%
10.5 lb 6 Row 37 2 88.4%

Strike volume was 8.5g. Calc said preboil vol is 8g. My kettle isn't marked, so I dont know for sure. Mash temp was between 158-148 for the 60 min. Full boil, no sparge.

 

[Scuba_Steve81]

Ok, my calc called for an OG of 1.052. My actual OG is 1.055. So I was pretty close. Just probably need to up my efficiency a few points.

 

[doug293cz]

Here are my parameters.

8 oz American - Caramel / Crystal 60L 34 60 4.2%
10 oz American - Victory 34 28 5.3%
4 oz. American - Chocolate. 29 350 2.1%
10.5 lb 6 Row 37 2 88.4%

Strike volume was 8.5g. Calc said preboil vol is 8g. My kettle isn't marked, so I dont know for sure. Mash temp was between 158-148 for the 60 min. Full boil, no sparge.

So 11.875 lb of grain with 8.5 gal of strike water yields a maximum mash wort/first runnings SG of about 1.045 - 1.046. To get a higher SG you need either more grain or less water. Thus one or more of the three measurements (SG, volume, weight) is in error.

Also, to get 8 gal of pre-boil from 11.875 lb of grain with 8.5 gal of strike water requires a grain absorption rate of (8.5 - 8.0) / 11.875 = 0.042 gal/lb, which an unrealistically low value. So, it looks like you have something set up incorrectly in the calculator you used.

Brew on

 

[Scuba_Steve81]

So 11.875 lb of grain with 8.5 gal of strike water yields a maximum mash wort/first runnings SG of about 1.045 - 1.046. To get a higher SG you need either more grain or less water. Thus one or more of the three measurements (SG, volume, weight) is in error.

Also, to get 8 gal of pre-boil from 11.875 lb of grain with 8.5 gal of strike water requires a grain absorption rate of (8.5 - 8.0) / 11.875 = 0.042 gal/lb, which an unrealistically low value. So, it looks like you have something set up incorrectly in the calculator you used.

Brew on

You know, I don't think my calculator has an option to input grain loss... Might email the developer. Maybe trub loss?

 

[doug293cz]

You know, I don't think my calculator has an option to input grain loss... Might email the developer. Maybe trub loss?

That calculator doesn't do arithmetic very well either. 7.95 gal (pre-boil) - 1.50 gal (boil off) = 6.45 gal (post-boil), not 6.2 gal.

I suggest you try the calculator here.

Edit: The volume discrepancies could be due to different measurement temps for the different values, but it's not obvious from the screen shot.
Brew on