Issue with low gravity

[BHive]

My last batch was supposed to be 1.070 after boil. It was only 1.050 and resulted in what I call a watered down version of what I intended. There were a couple of minor things that may have contributed to low gravity but I'd like to be sure the problem doesn't have to do with my water calculation.

I'm doing a 5 gal biab batch full volume no sparge. I'm using 13# of grain and adding 12 oz of sugar at flameout. 60 min boil. 1.5 oz hops for duration of boil.

Beersmith tells me my pre boil volume should be 7.6 gal, and so I want to start out with 34.45 qts or about 8.6 gals of water before dough in. Does this sound off to anyone? Again just want to eliminate this as the problem.

 

[BHive]

During chill, my wort chiller hose spring a leak which added a little extra water into my boiled wort. I figure only a cup or 2 of hose water max got in but that obviously didn't help. Also my boil wasn't vigorous and so I may not have had enough boil off

 

[TheMadKing]

My last batch was supposed to be 1.070 after boil. It was only 1.050 and resulted in what I call a watered down version of what I intended. There were a couple of minor things that may have contributed to low gravity but I'd like to be sure the problem doesn't have to do with my water calculation.

I'm doing a 5 gal biab batch full volume no sparge. I'm using 13# of grain and adding 12 oz of sugar at flameout. 60 min boil. 1.5 oz hops for duration of boil.

Beersmith tells me my pre boil volume should be 7.6 gal, and so I want to start out with 34.45 qts or about 8.6 gals of water before dough in. Does this sound off to anyone? Again just want to eliminate this as the problem.

What were your actual volumes compared to beersmith?

That seems high to me, I usually start with about 7.5 gallons preboil.

But if beersmith was saying you would hit 1.070 with that much water, one of two things went wrong:

You had more water than beersmith told you to, or your mash efficiency was very low..

EDIT: if you didn't measure your volumes, there's no way to know what happened. If your hose was leaking into your brew kettle and your boil off was low, then dollars to doughnuts thats your problem right there.

 

[enkamania]

You water to grain ratio may be a bit high, but my guess would be the crush not being fine enough. Also, not stirring well enough at dough in could be the problem.

 

[kh54s10]

Did you end up with the volume of wort into the fermenter that Beersmith was predicting? If instead of 5 gallons expected you ended up with 6 gallons your OG will be low. How much is able to be calculated.

If you ended up with the right amount into the fermenter the usual culprit is a poor crush on the grains.

For the mash you can calculate the grain absortion, then add enough water so that you end up with the amount you need for boil off.

Everyone's boil off will be a little different depending on: ambient temperature, ambient humidity, heat source and degree of heat, kettle material and kettle dimensions, etc. You will need to record your results and make changes in your equipment profile over a few batches to fine tune BS to give the proper ingredient amounts and water volumes.

 

[BHive]

Beersmith told me to start with 8.6 gal. So after grain absorption and mash my pre boil should have been about 7.6 gal. However, I didn't measure after I pulled out the bag and have it a sqeeze

 

[BHive]

Thanks. Could be I didn't stir well enough. Also the weak boil and hose leak. But does 8.5 gal (strike water) seem high for using 13lb of grain?

 

[BHive]

Did you end up with the volume of wort into the fermenter that Beersmith was predicting? If instead of 5 gallons expected you ended up with 6 gallons your OG will be low. How much is able to be calculated.

If you ended up with the right amount into the fermenter the usual culprit is a poor crush on the grains.

For the mash you can calculate the grain absortion, then add enough water so that you end up with the amount you need for boil off.

Everyone's boil off will be a little different depending on: ambient temperature, ambient humidity, heat source and degree of heat, kettle material and kettle dimensions, etc. You will need to record your results and make changes in your equipment profile over a few batches to fine tune BS to give the proper ingredient amounts and water volumes.

Yeah I had a little more left in my kettle than I expected. After fermenter was full I still had a decent amount left. Maybe 3/4 gal but again I did not measure that either

 

[brew703]

at most I would think only 7.5 gal total water was needed. so if you went with 8.6 gallons that would be why your OG was low.
Go to priceless brewing and plug in your info.

 

[kh54s10]

Yeah I had a little more left in my kettle than I expected. After fermenter was full I still had a decent amount left. Maybe 3/4 gal but again I did not measure that either

This is part of your problem but without accurate volumes you cannot be sure if there were other contributing factors.

Record your volumes and make adjustments in Beersmith. After a few you should be hitting your numbers closely.

Also check that you are getting a good crush on your grains. If you are getting them milled at your LHBS, make sure they know you are doing BIAB. Most will have their mills set fairly coarse so the traditional mash tun users do not get a stuck sparge.

 

[chickypad]

This is part of your problem but without accurate volumes you cannot be sure if there were other contributing factors.

Record your volumes and make adjustments in Beersmith. After a few you should be hitting your numbers closely.

^ This. It will be hard to troubleshoot the other stuff if you don't track your volumes, losses, etc. You should be telling Beersmith what to do, not the other way around. There are some preloaded profiles in there but you really need to tweak it correctly for your own system.

 

[kh54s10]

at most I would think only 7.5 gal total water was needed. so if you went with 8.6 gallons that would be why your OG was low.
Go to priceless brewing and plug in your info.

I was just thinking, I don't do BIAB much but Beersmith will be calculating your volumes accounting for grain absorption, if you squeeze the wort out of the grain, that amount will be too much. I don't think it accounts for squeezing the wort out of the grains.

You also need to account for boil off. In my 10 gallon pot on an SP10 burner I need just over 7 gallons to end up with 5 in the fermenter with a 60 minute boil. That is with a pretty vigorous boil.

 

[TexasWine]

My money is on a confluence of issues. Too much water, and a lower than anticipated efficiency.

1 gallon of absorption with 13 pounds sounds within reason, and sounds like that's what your settings in Beersmith are at. Just spitballing, but let's assume you boiled off 1 gallon and ended up with 6.5 gallons at flame out. With 60% efficiency, that puts your OG at 1.050.

Take volume measurements next time, along with gravity readings. Then armed with that info, someone on here will actually be able to help troubleshoot instead of just guessing. And don't forget to cool the sample if you're using a hydrometer!

View attachment 1483645954631.jpg

 

[PADave]

Too much water. Last brew I did with around 13# of grain I started with 7.5 gallons of water. That gets me 5.5 gallon into the fermenter. With your numbers you would have to have a 2.5 gal boil off.

 

[BHive]

Good stuff. Thanks everyone for the tips. Definitely going to measure the pre boil volume this time. And I'll start out with 8 gallons. Squeeze to get to 7.5 pre boil. Boil more vigorously and hopefully not have any leaky hoses. Brew day is tomorrow so I'll let yas know how it goes

 

[RM-MN]

Good stuff. Thanks everyone for the tips. Definitely going to measure the pre boil volume this time. And I'll start out with 8 gallons. Squeeze to get to 7.5 pre boil. Boil more vigorously and hopefully not have any leaky hoses. Brew day is tomorrow so I'll let yas know how it goes

If squeezing the bag doesn't get you quite enough for your pre-boil amount, pour the amount you are short into the bag of grains and squeeze again. You don't need to heat the water to do this.:rockin:

 

[BHive]

Today was a great success. I started with 8 gal. Squeezed til I got just over 7 gal pre boil. Hit my pre boil gravity and nailed the OG. This is looking to be a good batch