Getting frustrated...

[Ameritoon]

Ok - I'm confused - sorry for the ignorance - but I've seem some threads that are referring to first runnings, etc. when talking about BIAB?
I've done 2 BIABs so far. My second one (done yesterday) seems to be "OK" so far. But I think I'm screwing something up - because my numbers were low for the grain bill I had.
Basically - I brought 5 gallons up to 165F, added my grains 10.88#s, stirred and let sit for 60 (stirring every 15 mins - adjusting temps if needed). At this point I had a reading of 1.050 @ 100F (I pulled a sample and cooled) this should be about 1.056 @ 60F. I thought I finally had it nailed on!
After an hour I brought the liquid up to 170F stirring occasionally, pulled my grains. (Here is where I think I went wrong!) I didn't add any water at this point. I just brought my temps to boiling and then started the clock adding hop.
My ending volume was about 3.5gallons - which means to hit my expected volume I needed to add 1.5g. After adding this additionaly water my gravity was knocked down to 1.044 @ 75F (so approx. 1.046). Pitched S-05 - things were swirling nicely this morning... So this will be a decent APA - but not have the ABV I was shooting for.

What am I doing wrong??? I can give a more detailed run down, if needed.

 

[brew703]

Are you using software to determine how much strike water is needed? I am a BIAB brewer as well. I usually hit all numbers pretty close. I have noticed some efficiency swings which is really frustrating.
I've brew full volume and never had to add any top up water.
Try using priceless brewing's spreadsheet. I use it and never had an issue. http://pricelessbrewing.github.io/BiabCalc/
To brew a 5.5 gal batch, you would need approx. 8.5 gallons of strike water. How much did you use?

 

[LLBeanJ]

Your 1.044 could also be a measurement error due to incomplete mixing of the top off water. Did you take a gravity reading prior to adding water? This would be more accurate, as there would be no mixing issues. Then you could just do a little math to figure out what the gravity would be after adding a known amount of water without having to remeasure the gravity.

Edit to add: If I'm reading correctly, you had 5.0 gallons @ 1.056 (corrected for temp), boiled for an hour leaving you with 3.5 gallons. Then you added 1.5 gallons of top off water bringing it back to 5.0 gallons. If you started with 5.0 gallons and ultimately ended with 5.0 gallons in the fermenter, then the wort in the fermenter would have had to be 1.056. If your post-top off reading was 1.046 (corrected for temp), then that had to be an error due to incomplete mixing.

 

[bosster01]

If you have a 5 gallon recipe. You should be mashing with like 6 gallons of water to account for a 1 gallon boil off and a final volume of 5 gallons.

SOME people who BIAB (including me) will decide to mash at a normal mash thickness (1-2 qt water/lb grain) and then sparge the bag either by dunking it or by pouring the remaining water to get to my pre boil volume over the bag.

It sounds like you had poor efficiency otherwise it wouldn't have mattered if you did it the way you did. You might be able to improve efficiency by sparging. Also when I BIAB I always just add some extra base malt to account for the poor efficiency. For example I brewed a 1.068 IPA yesterday and it started with 12 lb of 2 row - I added an extra lb - and I ended up coming in exactly on my numbers (I also dunk sparged).

I hope that helps.

 

[ScrewyBrewer]

Brewing is a combination of wort volume and of alcohol content. What size kettle did you use, is that what limited your pre-boil volume? I calculate my pre-boil volume by working backwards using my packaged beer volume. Then add in more water for grain/hop absorption, kettle/fermentor trub loss and boil evaporation.

 

[Ameritoon]

@brew703 - I started with 5.0gal - I think this is where I'm going wrong.
@LLBeanJ - I took my measurement AFTER I added the 1.5 gal. Maybe I didn't mix enough?
@booster01 - The sparge water is where I think I'm losing my mind... I did NOT add additional water of any higher temps. I just brought my original volume up to temp. I think I need to heat an additional gallon or two to rinse the grains. This should give me a better starting volume (pre-boil).

 

[Homercidal]

A 5 gallon batch will need 5 gallons of water to start with. Then you have to factor how much water the grain will absorb, so add 1/2 quart per pound of grain. If you used 10 pounds of grain, then you need to add 10 x .5 = 5 quarts, or 1.25 gallons MORE of water to make up for what the grain will absorb.

On top of that you will lose 1+ gallons of water per hour of boiling. This varies by equipment and since you already brewed and figured about 1.5 gallons will be lost during an hour, add 1.5 gallons to your water requirements. 5 gallons to start + 1.25 gallons grain absorption + 1.5 gallons boil-off = 7.5 gallons of water total needed.

Of course this is a rough estimate and you will need to tweak it to match your system and methods. If you say you only lost 1.5 gallons during the brewday, then it seems you missed only one of these two factors and I misread your description of the problem.

 

[Homercidal]

Also, you don't have to sparge with BIAB if you don't' want to, unless your equipment can't hold the entire volume of water plus grain. When I BIAB in the house I sometimes use a ratio of 1.25 quarts of water to 1 pound of grain for strike water. Then I use the remainder as a dunk sparge then combine the two worts.

Most people I know who BIAB can do full volume and simply mash with all of it and then lift the bag up after the mash.

Rarely someone will mash a concentrated wort and then dilute with top-up water after the boil, similar to an Extract batch.

 

[Aristotelian]

Sounds like your efficiency is lower than your recipe. You should be fine topping off later if your efficiency is on target Low efficiency is not a problem per se, you just have to adjust for it in advance or compensate later. In this case, if your gravity was on target with only 3.5 G of wort, you shouldn't have topped off to 5 G.

What is your target efficiency, and what is your actual efficiency? (You can use an online calculator to plug in your grain bill and OG to calculate this number).

 

[boydster]

Your 1.044 could also be a measurement error due to incomplete mixing of the top off water. Did you take a gravity reading prior to adding water? This would be more accurate, as there would be no mixing issues. Then you could just do a little math to figure out what the gravity would be after adding a known amount of water without having to remeasure the gravity.

Edit to add: If I'm reading correctly, you had 5.0 gallons @ 1.056 (corrected for temp), boiled for an hour leaving you with 3.5 gallons. Then you added 1.5 gallons of top off water bringing it back to 5.0 gallons. If you started with 5.0 gallons and ultimately ended with 5.0 gallons in the fermenter, then the wort in the fermenter would have had to be 1.056. If your post-top off reading was 1.046 (corrected for temp), then that had to be an error due to incomplete mixing.

^^^ This right here. If you took an OG before you started boiling and got 1.056 with 5 gallons, and at the end you added top-off water to make sure you had the same 5 gallons of wort going into the fermenter (just compensating for the boil off), then you've got an OG of 1.056. Sugar can't evaporate, so you just got a low reading due to not having the extra water mixed in sufficiently.

 

[SoCalHomeBrew]

(Edit: looks like we all answered the same thing about the same time)

A couple of examples to draw conclusions from:

I use a 12 gallon pot for 5 gallon batches which I make full volume batches. I start by boiling 6 3/4 gallons of water. Mashing in this much volume is nice and soupy so efficiency is high without sparging. I lose about 1 gallons absorbed in the grains/evap leaving 5 3/4 gallons for the boil. I lose 3/4 gallons to the boil so after cold crashing the wort I end up with 5 gallons.

I used to use a 5 gallon pot to make 5 gallon batches which I made partial volume batches. I started by boiling 2.5 gallons of water. Mashing in this much volume was hard, really thick, and I had to lift the bag onto a large colander on top of my pot and sparge in 2 more gallons of water and press the grains to try and get good efficiency, often falling just short. I would lose 1 gallons absorbed into the grain but gain 2 gallons with the sparge. I would boil at 3.5 gallons to leave enough head space to prevent boilover. At the end of the boil I would insert my wort chiller and top up my water to the top, then cold crash. After removing the wort chiller I would top up with my remaining post boiled and now cooled sparge water the last 1/3 gallon I needed to complete 5 gallons, mix/airiate well, and take my gravity readings.

It sounds like you are somewhere between the two instances above. Some things to note are the amount of water absorbed by the grains and that affect on gravity readings. Starting with 5 gallons, you are really only reading 4 gallons (concentrated) gravity readings as 1 gallon was absorbed in the grains. At various stages of your process, your actual available volume may not be your final 5 gallons so accommodate accordingly with your readings so you are not surprised when you dilute the final and the readings drop. Partial mashes require sparging, full mashes often don't.

 

[Ameritoon]

@boydster - that's what I was hoping on too...

@SoCalHomeBrew - I am using an 8 gallon pot, so I can easily do the 6+ gallons up front. I have another 2 gallon pot that I could/should heat up for a sparge. I will need to mark off "levels" I guess, since the pot doesn't have a glass window to indicate volume (can't think of the name).

 

[RM-MN]

@boydster - that's what I was hoping on too...

@SoCalHomeBrew - I am using an 8 gallon pot, so I can easily do the 6+ gallons up front. I have another 2 gallon pot that I could/should heat up for a sparge. I will need to mark off "levels" I guess, since the pot doesn't have a glass window to indicate volume (can't think of the name).

You think that you can do 6+ gallons but when you add the grain you will be pretty close to the top of the kettle. Plan on using no more than 6 gallons of water for the strike, perhaps even a little less as your grain will take up quite a bit of the open room.

You don't need to heat water for sparge, cold water will get you nearly the same extraction efficiency. When you pull the bag and let it drain or squeeze you can get an idea of how much wort you have. Sparge with the amount needed to reach the expected pre-boil, probably about 6 1/2 gallons total.

 

[Ameritoon]

@RM-MN - thanks pal.

 

[Ameritoon]

Just an update... that batch is percolating away - yeasties are happy, flying about the carboy... decent krausen (for S-05). I can smell the Mosaic hops coming up and through the airlock... smells lovely! Later this week I'll dry hop another ounce of Mosaic.