I had my first AG brewday yesterday, and for the most part it was a rousing success. Despite spilling about a pint or two of my strike water, I was within a degree of my target mash temp. I’m doing BIAB, but with a separate mash tun. This means I don’t need to futz around with the heat on my stove to hold my mash temp. Plus, I have it rigged so I can suspend the bag off the bottom of the tun once I drain it and then squeeze the hell out of it against the side of the cooler. I only lost a bit under 1/2 gallon to 6.25 lb of grain.
The biggest surprise was my efficiency. I based my recipe off a 70% brewhouse efficiency. Since I don’t get a big boiloff, I need a thicker mash than most BIABers and I guessed low on my target efficiency. Turns out I hit a bit over 79%.
So now my questions. I lost about 4-5 degrees F during a 90 minute mash. This seems reasonable to me, but how does this compare to everyone else? I can’t help but wonder if the grain bag may be wicking off a bit of liquid and cooling things down.
Also, my next brew is going to be a Barleywine at about 1.100 OG. Anyone have a guess how much efficiency I may end up losing brewing something this big? Obviously, the actual number will be specific to my system, but what kind of ballpark would you expect if you were batch sparging (for example)?
Figuring out all those variables on your system is an important part of learning your system and then being able to adjust recipes accordingly. How much heat is lost in each step, how much volume is lost, how long it takes, overall efficiency, etc. Those are unique to your system and methods. So measure carefully and then you can take them into account the next time you brew. Some variables will differ from batch to batch, so try to learn the range of them on your system.
If you’re losing too much heat from your mash tun, insulate it. Easiest way is to buy some of that duct insulating stuff with the small bubbles and aluminum kind of stuff on both sides and wrap that around your pot. Buy it at a home center. Use a bungee cord or strap or something and wrap it 2 or 3 times around. That should reduce your heat loss. Covering the pot is important, but I’m guessing you’re already doing that.
Losing 4-5F over 90 min is pretty good, IMHO. I’d lose 8-10F in that same time on my half barrel system over the same time, but I get that down to 1-2F by insulating. 90 min is a long time to mash, though. Sure you need all that time?
I did a 90-minute mash since that’s what many of the Aussie BIABers seem to do. Also, being the first time I brewed with this setup, I wasn’t sure what kind of brewhouse efficiency I was going to end up with. Since I’m pretty happy with the efficiency I got, I will probably go for 60 minutes next time and stick with that if my efficiency remains in the 70’s.
Thanks for the insulation tips. I’ll definitely try that out if temp loss becomes a problem.
[quote]Also, being the first time I brewed with this setup, I wasn’t sure what kind of brewhouse efficiency I was going to end up with.
[/quote]
Keep good notes on everything, it’ll take a number of brewdays before you get a good feel for what to expect. Be prepared to adjust for lower or higher efficiency than expected. Most of all, have fun with it
Isn’t he going to extract tannins if he squeezes the bag? DGMR I’ve done it a few times back in the extract days and still made very good beer, just thought I’d ask…
This is pretty much standard practice with BIAB. I think that the bag squeezing thing has pretty much been debunked. Tannin extraction is generally caused by pH and/or oversparging. Maybe in an extract batch where you don’t generally make water adjustments this may be more of an issue.
I squeeze the crap out of my bag and not once have I had a problem. My friends rave about my beer but I’m just lucky so far.
In BIABing, I think the worse you can do to bring tannins out is to go over 170 in your mash out. I try to stick to 168 just in case and it’s worked very well for me. I get efficiencies in the upper 70’s and lower 80’s but really don’t worry about that much at all. I try to mash for 70 minutes plus the mash out and do a good squeeze after the bag drains and then boil away.
Brew In A Bag - you essentially line your brew kettle with a mesh bag and mash your grain in there. Once the mash is done, you simply pull the bag out and begin your boil.
I used to squeeze my BIAB like it owed me money, until I had 7 or so very astringent batches of BIAB in a row. I traced the problem back to getting too much draff into my kettle. My pH was right (verified with a pH meter) and my sparge temps were always below 160*F.
In beers I’ve tried at my homebrew club, excessive tannin extraction is fairly common, and hard to diagnose at low levels. Since shifting to a cooler MLT and being really uptight about conditioning and milling my grain, my beers have gotten much “smoother” and less “angular.” I think in low levels excessive tannins just make the beer seem a bit off, but if it’s a flavor that’s present in all of your brews, it’s hard to notice. I know I didn’t notice until I made the switch. I’m assuming I’m not the only bag-squeezer who wrongly thought their beer was fine.
Well, I am only doing 2-3 gallon batches so I’m looking at maybe 10 pounds or so. In BIAB, the grain typically holds a lot less liquid since your mash is so thin. It’s really not as bad as people make it seem. A lot of the Aussies use a pulley system if they’re devoted BIABers doing 5 gallon batches. What is more appealing would be to just pull the bag, wait 30 seconds or so until it slows to a drip, then put the bag in a large bucket to let it continue to drain as you begin to heat the wort.
I’ve come up with a bit of a simpler solution for my setup since I use a separate mash tun:
