First BIAB Questions

[Brad21Z]

Need a little help here from some experienced brewers. I have a pumpkin recipe from last year I want to brew. Problem is I'll be using BIAB when we used the complete all grain set up and sparged last year. So here are my concerns. How do I know how much water and what temp I'll need before adding the grains. Should you squeeze the bag or do any sort of sparging? Any other differences using BIAB I'm missing?

 

[chickypad]

The best calculator I've seen for BIAB is priceless brewing's here. If you can fit the full volume mash great, but there is also an option to add a sparge if you can't (I prefer dunk sparge myself but you can also do a pour over the bag). With the full volume thin mashes you could run into pH issues so pay attention to that. And yes, squeeze, squeeze away!

 

[wilserbrewer]

I have never brewed with pumpkin, so that being said this is what I would do....

Since mash calculators don't make an allowance for adding pumpkin, I would mash in with 60% of your total water at a guesstimate of 158-160 expecting your resultant mash temp to be a little low. Then I would carefully raise the mash temp with small additions of boiling water, or a couple ice cubes if you are too high. Let the mash rest and pull the bag when done mashing, measure first runnings and do a batch sparge of the amount needed to reach preboil volume.

Or you could just use priceless's calculator, and assume the pumpkin needs no additional water, and raise strike temp by a degree or two to account for the pumpkin addition.

With the pumpkin addition, you'll have to wing it a wee bit.

 

[pricelessbrewing]

Since mash calculators don't make an allowance for adding pumpkin

Don't tempt me!

 

[mathin]

Pumpkin can clog the bag which causes major issues when raising the bag for draining. I recommend putting the pumpkin in a smaller bag (like you might use for hops during the boil or dry hopping) which traps the pumpkin fibers before they can clog the grain bag. You can remove it before hoisting the grain bag. I learned this the hard way ... My second pumpkin beer was much easier with the second bag and I don't think the pumpkin character was affected by the smaller bag.

Also, if you are roasting the pumpkin purée either make sure it has time to cool, or use much cooler strike water.

 

[Brad21Z]

Over the weekend I made the pumpkin beer I had been planning on making. Only issue I had was OG was supposed to come out at 1.068 and I only managed 1.046. Now I didn't squeeze the bag since I heard varying opinions on this and didn't sparge because my pre boil volume was right where I wanted it to be. Is this simply due to the fact I didn't squeeze or sparge? Should I adjust my mash volume water down a little that it would allow me to sparge if needed? One other note, I may have steeped my gains on the higher end (about 158 degrees) as I was expecting temp drop but never got any.

 

[william_shakes_beer]

You do realize that the flavor you usually asociate with pumpkin comes from the spices, not the pumpkin. I have done 4 pumpkin beers in my careed. The last 3 with spices only.

 

[Brad21Z]

You do realize that the flavor you usually asociate with pumpkin comes from the spices, not the pumpkin. I have done 4 pumpkin beers in my careed. The last 3 with spices only.

Yes and I used spices as well. I've used this recipe before in a traditional 3 vessel set up and it's turned out very well. My only concern is not reaching my targeted original gravity using BIAB method.

 

[pricelessbrewing]

Over the weekend I made the pumpkin beer I had been planning on making. Only issue I had was OG was supposed to come out at 1.068 and I only managed 1.046. Now I didn't squeeze the bag since I heard varying opinions on this and didn't sparge because my pre boil volume was right where I wanted it to be. Is this simply due to the fact I didn't squeeze or sparge? Should I adjust my mash volume water down a little that it would allow me to sparge if needed? One other note, I may have steeped my gains on the higher end (about 158 degrees) as I was expecting temp drop but never got any.

Biab has a couple main advantages over traditional mashtun brewing, one is you can use a finer crush which provides a better efficiency. The other is squeezing the bag, which provides a higher brewhouse effeciency due to reduced losses. My guess is the high temp didn't help much, but that usually affects the FG more than the OG, as long as it was within mash temps. If it was actually above 158 then it might've hurt a bit more.

Not squeezing probably hit your effeciency more than you might realize, roughly OG might've been around 1.056 or so due to gaining another .75 gallons or so depending on your grain bill.

 

[Brad21Z]

Biab has a couple main advantages over traditional mashtun brewing, one is you can use a finer crush which provides a better efficiency. The other is squeezing the bag, which provides a higher brewhouse effeciency due to reduced losses. My guess is the high temp didn't help much, but that usually affects the FG more than the OG, as long as it was within mash temps. If it was actually above 158 then it might've hurt a bit more.

Not squeezing probably hit your effeciency more than you might realize, roughly OG might've been around 1.056 or so due to gaining another .75 gallons or so depending on your grain bill.

Thanks for the advice. Just curious, why is squeezing considered a good process in BIAB when I thought any sort of compression in a traditional 3 vessel system is a no no. I had heard squeezing can result in off flavors and such.

 

[wysiwyg]

There's a pretty even split amongst people's opinions on squeezing - either do it with earnest, or don't do it at all. Squeezing will not raise OG, only volume. Personally, I squeeze, but only to reach desired pre-boil volume. Even when I've had to squeeze hard to get volume, I haven't experienced any off flavors. I also squeeze my hopsock, but that's to get all the flavor! When reading other opinions on squeezing, try to determine if they've ever tried it or are just speculating.

BTW, last weekend I made my first BIAB pumpkin ale with 2 15oz cans of pumpkin, and I put the pumpkin in my hopsock 10 minutes before end of boil. Spice went directly into the kettle. My irish moss goes into the hopsock too - anything to keep big junk out of the plate chiller.

 

[Brad21Z]

There's a pretty even split amongst people's opinions on squeezing - either do it with earnest, or don't do it at all. Squeezing will not raise OG, only volume. Personally, I squeeze, but only to reach desired pre-boil volume. Even when I've had to squeeze hard to get volume, I haven't experienced any off flavors. I also squeeze my hopsock, but that's to get all the flavor! When reading other opinions on squeezing, try to determine if they've ever tried it or are just speculating.

BTW, last weekend I made my first BIAB pumpkin ale with 2 15oz cans of pumpkin, and I put the pumpkin in my hopsock 10 minutes before end of boil. Spice went directly into the kettle. My irish moss goes into the hopsock too - anything to keep big junk out of the plate chiller.

I also used a very fine mesh bag for my pumpkin. That seemed to work really well. Any input on what caused my low OG?

 

[doug293cz]

I also used a very fine mesh bag for my pumpkin. That seemed to work really well. Any input on what caused my low OG?

Need to know your recipe, strike water volume, pre-boil volume (and temp at which measured) and pre-boil SG to have a go at diagnosing your efficiency issues.

Brew on

 

[Gavin C]

. Squeezing will not raise OG, only volume.

Not exactly correct.

Squeezing will get more sugars out of the grain/sweet-wort mix in the bag as more sweet-wort of the same specific gravity flows into the kettle.

More sugars in the kettle can lead to a higher or lower OG depending on the boil duration.

The OG is the gravity when it gets to the fermentor not preboil.

Squeezing and tannins/astringency requires a ph above 6.0 and a temeprature of 170F+.

Someone posted an article about a commercial brewery using a press to squeeze their mash's spent grains to extract greater volumes of sweet-wort.
Alaskan brewery

Same idea, no problem. I guess most commercial breweries will use some form of centrifuge to maximize lautering efficiency which is what a squeeze acomplishes. A centrifuge would negate any benefit of a squeeze. This is conjecture on my part. I have never been to a commercial brewey but reckon efficiency is a major priority.

 

[wysiwyg]

Not exactly correct.

Squeezing will get more sugars out of the grain/sweet-wort mix in the bag as more sweet-wort of the same specific gravity flows into the kettle.

More sugars in the kettle can lead to a higher or lower OG depending on the boil duration.

The OG is the gravity when it gets to the fermentor not preboil.

Squeezing and tannins/astringency requires a ph above 6.0 and a temeprature of 170F+.

Someone posted an article about a commercial brewery using a press to squeeze their mash's spent grains to extract greater volumes of sweet-wort.
Alaskan brewery

Same idea, no problem. I guess most commercial breweries will use some form of centrifuge to maximize lautering efficiency which is what a squeeze acomplishes. A centrifuge would negate any benefit of a squeeze. This is conjecture on my part. I have never been to a commercial brewey but reckon efficiency is a major priority.

Thanks for the reference to commercial brewing - I knew they incorporated some 'squeezing' techniques to reduce inefficiencies, but didn't have time to find actual references.

My bad on saying OG - I meant SG. Squeezing will not increase SG, only increase volume of the same SG.

 

[Gavin C]

Thanks for the reference to commercial brewing - I knew they incorporated some 'squeezing' techniques to reduce inefficiencies, but didn't have time to find actual references.

My bad on saying OG - I meant SG. Squeezing will not increase SG, only increase volume of the same SG.

No worries, glad I could dig it up. i think it may have been @doug293cz who mentioned it in another thread. Could be wrong there. No biggie

I should have realized it was just a typo on your part. When I reread, I was thinking, I'm sure he/she meant SG. Sorry for my pedantic response. I'm an avid squeezer. Not so much for the eking out efficiency but for the consistency.

I squeeze it to near its max so each brew get's the same treatment and I know what to expect in terms of consistent volume losses. (0.045 gallons/pound)

 

[Brad21Z]

Need to know your recipe, strike water volume, pre-boil volume (and temp at which measured) and pre-boil SG to have a go at diagnosing your efficiency issues.

Brew on

Batch size: 5.00 gal
Pre boil: 6.5 gal
Post boil: 5.5 gal
Boil time: 75 minutes

Ingredients:

10lbs pale malt (2 row)
3 lbs 8 oz pumpkin puree
2 lbs 12 oz oats, flaked
1 lb caramel malt 120L
8 oz caramel malt 60L

I heated 8.25 gallons of water to 165 and added above ingredients, bringing water temp down to 158, mashed for 60 minutes,temp stayed consistent, never added more heat.

Pulled the bag and was left with 6.5 gallons so I didn't squeeze the bag.

Started boil, added 1.75 oz of Mt Hood hops at 15 minute mark.

Added various spices with 5 minutes left.

Cooled wort to about 75 degrees, let sit for 2 hours to cool further. Took gravity reading and measured 1.046. Pitched yeast.

Anyone see where I went wrong?

 

[doug293cz]

Batch size: 5.00 gal
Pre boil: 6.5 gal
Post boil: 5.5 gal
Boil time: 75 minutes

Ingredients:

10lbs pale malt (2 row)
3 lbs 8 oz pumpkin puree
2 lbs 12 oz oats, flaked
1 lb caramel malt 120L
8 oz caramel malt 60L

I heated 8.25 gallons of water to 165 and added above ingredients, bringing water temp down to 158, mashed for 60 minutes,temp stayed consistent, never added more heat.

Pulled the bag and was left with 6.5 gallons so I didn't squeeze the bag.

Started boil, added 1.75 oz of Mt Hood hops at 15 minute mark.

Added various spices with 5 minutes left.

Cooled wort to about 75 degrees, let sit for 2 hours to cool further. Took gravity reading and measured 1.046. Pitched yeast.

Anyone see where I went wrong?

I calculate your lauter efficiency at 71% - 72%, and an expected pre-boil SG of 1.056 - 1.057 for 100% conversion (guesstimating contribution of pumpkin @ 16 pts/lb.) That would have put your post-boil gravity at 56.5 * 6.5 / 5.5 = 66.8 => 1.067. Your efficiency works out to 46 * 5.5 / 526 = 0.48 => 48% (526 is my estimate of potential points.) Assuming my lauter eff estimate is close to reality, that means your conversion efficiency would be 48 / 71.5 = 0.67 => 67%. That's pretty bad conversion efficiency.

Things that might account for your poor conversion efficiency:

• Grain crush to coarse to complete saccharification in time allowed.
• pH outside the range of 5.2 - 5.7. This could slow down the saccharification reactions.
• Mash temp high enough that amylase enzymes denatured before saccharification was complete. Crush could interact with this.
• Pumpkin did something to interfere with the action of the amylase enzymes.

Edit: not sure how pumpkin might have affected the mash pH, but it is something you might want to check into.
Brew on

 

[Brad21Z]

I calculate your lauter efficiency at 71% - 72%, and an expected pre-boil SG of 1.056 - 1.057 for 100% conversion (guesstimating contribution of pumpkin @ 16 pts/lb.) That would have put your post-boil gravity at 56.5 * 6.5 / 5.5 = 66.8 => 1.067. Your efficiency works out to 46 * 5.5 / 526 = 0.48 => 48% (526 is my estimate of potential points.) Assuming my lauter eff estimate is close to reality, that means your conversion efficiency would be 48 / 71.5 = 0.67 => 67%. That's pretty bad conversion efficiency.

Things that might account for your poor conversion efficiency:

• Grain crush to coarse to complete saccharification in time allowed.
• pH outside the range of 5.2 - 5.7. This could slow down the saccharification reactions.
• Mash temp high enough that amylase enzymes denatured before saccharification was complete. Crush could interact with this.
• Pumpkin did something to interfere with the action of the amylase enzymes.

Edit: not sure how pumpkin might have affected the mash pH, but it is something you might want to check into.
Brew on

Wow that's a lot of information to digest lol. I really appreciate your response. I'll have to check a few things and make some modifications for next time. Guess time will tell how this one turns out but it's a learning process. Thanks again.

 

[pricelessbrewing]

Good info as always @doug239cz