Pre boil gravity too high, finish ok though

[shemp]

Brewed an ag ipa yesterday and had a weird gravity reading. I wanted to mash at 153 but ended up with 149 (after adding 12 oz of boiling water). My pre boil gravity was 1.072 instead of the estimated 1.059. Yes, I corrected for temp and quantity was accurate. The post boil gravity was right on the estimate of 1.066 with my volume being a bit low, about 8 oz. I'm trying to figure out why the pre boil grav was so high yet it finished fine.

What does a cooler mash temp do? I also never reached 170 on my mash out. Everything ran cool yesterday.

Thanks

 

[Hello]

Cooler temps at mash make for a beer that could finish lower. That temp is going to give you a drier beer, I wouldn't get all wiggly about it. What I cannot see is how you got such a high gravity preboil. Usually the gravity is low and boiling increases it because it reduces the wort essentially. While you adjusted for temp, I believe the reading was off. Did you use a hydrometer to measure the gravity? Although you corrected for temp, I wonder if it was just too hot resulting in a bad reading in spite of using a temp correction calculation.

 

[tally350z]

The cooler the mash temp the lower the FG could be. Mashing anywhere between 147-152 provides for a thinner beer. Mashing higher than that provides for a higher FG. I usually mash my IPA's around 148, and end with a FG around 1.010.

At what temp did you take the gravity reading? You want to try to get the temp as close to 60 as possible. Have you calibrated the hydrometer with distilled water to make sure it reads properly? Anything above 110-115 I wouldn't really trust even with the adjustment for the temps. Get it as close to 60 as possible. With such a higher gravity than expected I would say it was either your reading at such a higher temp or your volume was off. Either that or you got better efficiency than you normally do.

 

[chickypad]

Obviously at least one of the readings is wrong since it's impossible to go down in gravity after boiling off. As mentioned I wouldn't trust the correction factors at high temps, I always cool down below 75 at least. The other possibility is that your preboil wort wasn't mixed well and you were mostly measuring first runnings.

 

[Hello]

The cooler the mash temp the lower the FG could be. Mashing anywhere between 147-152 provides for a thinner beer. Mashing higher than that provides for a higher FG. I usually mash my IPA's around 148, and end with a FG around 1.010.

At what temp did you take the gravity reading? You want to try to get the temp as close to 60 as possible. Have you calibrated the hydrometer with distilled water to make sure it reads properly? Anything above 110-115 I wouldn't really trust even with the adjustment for the temps. Get it as close to 60 as possible. With such a higher gravity than expected I would say it was either your reading at such a higher temp or your volume was off. Either that or you got better efficiency than you normally do.

That's right. I totally mixed that all up.

I agree with you, if the wort was super hot then even adjusting the temp using a calculator wouldn't really make me feel confident that I had the right number. That is also a great point about first runnings. My first runnings of my last beer were 1.080, the second runnings combined with the first resulted in 1.055. Boiling for an hour gave me a 1.062 beer.

 

[shemp]

I only corrected from 80 so I doubt that's it. I think chickypad got it. My first running grav was 1080.

Thanks guys.

Bubbling away