pre boil gravity

[mikelt79]

Hello all,

I am not sure of my question here so I will lay down my scenario. I brewed a pale ale this past weekend. I mashed 10lbs of 2 row pale and 1lb of crystal 40 for 60min at 150deg. I sparged for 45min with liquor that was 155deg. Somehow I lost heat from 170. Anyway, I took a preboil reading but screwed up and only took it from the last bit running out of my MLT. The reading was 1022. I imagine that the true reading was a bit higher. I did an iodine test and the wort was really sweet to the taste, so I am assuming that converion took place. My PH was between 5.0 and 5.5. I boiled 6.5 gallons for 90min. My post boil gravity was 1064! This seems really high. Can I reverse calculate to get the true pre boil?? You never can calculate a true post boil in my opinion. I guess what I am asking is , is my post boil off the charts? is the beer going to be to sweet? She is fermenting like a hurricane so I am hoping to get back down to 1020 at least. Any help would be greatly appreciated.

Best,

Mike

 

[shogun0660]

I think you should be able to calculate the pre boil gravity, assuming you have a reasonable idea of what the post boil volume is.

Just take 64 (from your SG of 1.064) x post boil = pre boil vol x pre boil gravity points (for example, if 1.050, would be 50).

A little algebra, and assuming you got around 5 gallons:
64 x 5/ 6.5 gallons = 49
So preboil in that scenario would be 1.049.

hope that helps. Learned this from Ray Daniel's great book, "Designing Great Beers." Worth checking out.
take care, happy brewing

R

 

[Polboy]

Your preboil should be taken from the BK after you collect and mix all the runnings (mash+sparges) before you start boiling and should be taken or adjusted at 60F temp, when you boil it some of the H2o evaporate and you increase SG, you can calculated by knowin how much you evaporated but its not very importent as postboiling SG reading is more important. Usually higher SG=more alcohol and it doesnt have to be too sweet, sweetens is determine by FG and this is influence by mash conditions and fermentation

 

[geer537]

You should be fine- I just had an IIPA that started at 1.080 finish at 1.009. I used Pac Man at 64 degrees.

What kind of yeast did you use? I beleive that and the fermentation temps will be more of a factor in determining if you'll have a super sweet beer. Assuming your 60 minute mash at 150 held temps well, you should have converted the starches correctly and it be should be pretty fermentable. Or maybe I misunderstood.

 

[mikelt79]

Thanks guys much obliged! To answer you all in order:
Shogun: Thats exactly what I did and came up with same, thank you!
cciszew: Exactly! Like I said I screwed up with reading, thank you for the reminder, haha

geer 537: I actually just finished an IPA that started at 1079. I am on my second week of conditioning in secondary and I ahve only gotten down to 1019, not what I was looking for. I used white labs english dry ale with 2 litre starter. We will see as i am bottleing this weekend.
As for the yeast I recently used, I went with white labs san diego super. She took off like a raped ape and I will take a reading this weekend. I have heard good things so I will report back.
Thanks again guys and be easy!

Mike