First BIAB and OG is way off

[GeekBrew]

Brewed my first BIAB batch today. It was northern brewers chocolate milk stout. Followed the directions as specified. It’s a 3 gallon batch. They say OG should be around 1.052. Mine came out around 1.066. Started with a little more than 4.5 gallons of water as they suggested and boiled down to the 3 gallons. Did their additional mash out bringing the mash up to a temp of 168 for 10 minutes which they say could be optional. I don’t think that 10 minutes would make that drastic of a difference though? Any suggestions for future batches to help prevent this are much appreciated.

 

[Lefou]

I wish I had your problem.
You obviously got a great conversion, better efficiency, and better yield from your grains than expected. One way to compensate is by diluting your wort to a predictable pre-boil gravity. On my first few AG brews I made my numbers but they were to the low side.
My grist recipe for malts get calculated for a 70% efficiency to the BJCP gravity range for style. I compensate with a bit of extra grain to get there.

 

[mj1angier]

Yeah, getting a high SG is not a bad thing, easy to bring it down. Just means you get more beer. Do the same batch again. If numbers come out the same, you know that you can adjust things to hit the SG you want

 

[PADave]

No need to mash out with BIAB. Just pull the bag.

 

[RM-MN]

Brewed my first BIAB batch today. It was northern brewers chocolate milk stout. Followed the directions as specified. It’s a 3 gallon batch. They say OG should be around 1.052. Mine came out around 1.066. Started with a little more than 4.5 gallons of water as they suggested and boiled down to the 3 gallons. Did their additional mash out bringing the mash up to a temp of 168 for 10 minutes which they say could be optional. I don’t think that 10 minutes would make that drastic of a difference though? Any suggestions for future batches to help prevent this are much appreciated.

Take note of the amount of base malt and the crush you got. Brew another batch and compare. Brew another batch and compare. If you get similar results, use some software and change up the expected efficiency to reflect what you got. Reduce the amount of base malt in the software recipe to reflect what you want for OG and brew again. Don't change anything in the recipe but the base malts.

 

[r4dyce]

Kind of funny, I've experienced the same thing. I'd always read that efficiencies go down using BIAB method, but ever since I switched to it I routinely get very very high efficiencies, much higher than expected. I don't exactly know the cause, but I attribute it to the finer crush over compensating for any loss by using a bag with the grain.

 

[bigdawg86]

Do you squeeze your bag? I am often plagued by ignoring to the saying "the enemy of good is better".

I did my first BIAB and being somewhat paranoid about low efficiency I double ground the grain, essentially pulled about 2 gallons water to essentially sparge the bag, then I squeezed the bag. I wouldn't be surprised if my gravity is severely over shot haha... I haven't taken a pre-boil gravity yet though as I am currently kettle souring the batch. On the plus side, I like the idea of having the option to keep the beer higher gravity, or dilute to and have more beer!

I would even routinely get higher gravity with extract when using specialty grains... because I wanted to practice for all grain, I would essentially mash those at 154° for 30-45 minutes... even though there not supposed to contribute significantly to gravity I do believe there was some low conversion as my gravity was always higher than expected.

 

[GeekBrew]

I did not squeeze the bag, but I did lift and hold over the kettle for a while to let gravity drain a good amount of liquid out.

I am thinking that the lactose that was added may have created the higher than expected OG even though the recipe knew the lactose was being added. Thoughts on that?

 

[Biscuits]

What was your volume to fermentor? If you netted 3 gallons into the fermentor and have a higher OG than expected, then yes your efficiency is better than the recipe expected. However, if you only got 2.5 gallons into the fermentor this just means your volumes are off which would result in a higher OG.

I am suspecting this is the case as you started with 4.5 gallons of water and you didn't squeeze the bag which typically gives you a grain absorption rate of about .12 gal/lb of grain...so when you started your boil you were probably just north of 3.8 gallons of wort...assuming a typical boil-off rate of 1 gal/hr..you probably only transferred somewhere around 2.8 gallons of wort. This alone wouldn't increase your OG by .014 pts....However, the devil may be in the details.....did you use the entire bag of lactose? The recipe says to only use a little more than half of the bag.

https://www.northernbrewer.com/documentation/allgrain/BIAB-AG-ChocolateMilkStout.pdf

 

[GeekBrew]

Thanks for the feedback @Biscuits. You have much better calculations than me, but I did try to account for the fact that I would have needed additional water from the start. When I said in my original post that i started with "a little more than 4.5 gallons", I actually started with about 4.75 gallons of water (not exact measurement but just by my eye). And while I didn't squeeze the grains, I did allow them to drain back into the kettle while I was bringing it to a boil. Before boil, I was right above the 4 gallon mark. After cooling i was right around the 3 gallon mark. Now this is based on assuming that the gallon marks on my pot are correct! Also I did not use the entire packet of lactose. I should have been right in the 0.6lb range, but will put what is left on my scale to verify again either today or tomorrow. I always try to make sure to stick to the details with recipes. My previous batches (all extracts) have come out right on for OG and FG. I just got another 3 gallon BIAB kit from northern brewer for their dead ringer IPA. It will be interesting to see how close I am on that one.

 

[Biscuits]

Hmm, well in that case, there must be something to explain the increase in efficiency because it sounds like you accounted for losses and everything else.

 

[GeekBrew]

so i got another scale to verify how much lactose i put in. It was a 1lb bag and called for 0.6lb to be added. Putting the left over lactose in bag on the scale came out to 0.415 lbs, so it looks like I was pretty close with initial measuring. I guess the important piece now is to see how it tastes in a few weeks.