How long can I boil?

[Nigel]

I did my first all grain big beer a few weeks ago (a 5 gal batch of imperial stout). It all went a bit wrong - the OG was 1.071 when it should have been 1.096 I am pretty sure I know where I messed up - I don't think I lautered or boiled for long enough. I did all of the calculations with BeerSmith so I am pretty sure I got my volumes correct, I hit all of my mash in and mash out temps etc. etc.

I did a fly sparge, lautered until I hit my boil volume (6.5 gal) and boiled for 60 min. I was really bummed when I measured the OG after the boil but I think I figured out the problem - when I drained the mash tun when cleaning up after the boil, the wort that came out was really sticky sweet. My assumption is that rather than stopping collecting wort when I reached my boil volume I should have kept collecting until the gravity of the runnings reached around 1.008. Is that reasonable? If that is the case, what happens if I ended up with say 7.5 - 8 gal of pre-boil wort? Could I boil for 2-3 hours without messing up the flavor of the beer?

Any suggestions would be greatly appreciated - I'm brewing again tonight and although the OG is a little lower (1.075) I don't want to run into similar problems. Thanks in advance!

 

[wilserbrewer]

Yes you can boil longer without "hurting the beer". You will get a touch more caramel flavor and color. Rathr than looking to boil longer...also look closely at your sparge process. If your remnants in the MT were sticky sweet, your sparge likely failed...I would sugggest trying a batch sparge or even a double batch sparge.

Long boils are common for very large beers to help efficiency.

 

[billl]

You can boil the wort longer. I haven't done 3 hours, but I'm sure someone around here has.

The flip side is to just add more grain to start. It's pretty challenging to get great efficiency numbers for high gravity beers. You can fight that battle by keeping the mash loose and then boiling out the excess water OR just just brew as usual but up the grain bill to account for the lower efficiency.

 

[GilSwillBasementBrews]

You can definately boil larger volumes of wort for longer times to concentrate your wort to raise your OG. I also would batch sparge. Drain off your first runnings and your sparge water give a good stir, let it rest then vorlauf??SP?? And take your second runnings. Just my .02 I'm sure some of the more advanced brewers could chime in with better advice.

 

[helibrewer]

That is the difficulty of big brews, the grain bed gets so deep that it is hard to sparge well without using a lot of water...and increasing your boil time accordingly. In a pinch you can add DME, it will give you about 7 pts per pound at a 5 gallon volume. You would have needed about 3.5 pounds and might not want to add that much but it can be a time/efficiency saver when things go pear shaped.

 

[Nigel]

Okay, thanks for all of your help. I think I'll give batch sparging a go tonight...

EDIT:

The batch sparging worked really well last night. Managed to get about 76% efficiency (I could never get over 70% with fly sparging, even with small beers). Very impressed - much quicker and far less mess I guess my other cooler that I used for the fly sparging can sit around and collect some dust from now on!