Very low post mashing volume

[deeve007]

Hey guys,

Pretty sure issue is due to my newby-ness, but hopefully something simple to identify the issue...

For my second ever BIAB, did an oatmeal stout 20L batch... so began with 12 litres of water heated up, added grains in bag and left for 90 minutes as per recipe... when removing grains, there was less that 5 litres of water left. I did sparge, but that seems a LOT of water to add/sparge with to get back to the volume it should be, no?

Now one issue that may have caused or impacted on this: My recipe provider, they mill the main grains (pilsen), but not the "speciality" grains. Even after I asked them to do so, they told me to do them just before I mash, but I don't have a mill so not really an option.... but a bit of googling, I saw that some said that you can use a blender. So I tried this, but it did end up with some much finer grains that normal milling would have delivered. So would this have soaked up more water than usual?

(and yes, I need to find another recipe provider who will mill all grains for me...)

 

[balrog]

Grains will soak up about 1/2qt/lb (~1.04 l/kg)
Without knowing the grist weight, I'm guessing somewhere around 4.5kg? But that doesn't explain 7liter absorption. How long did you drain the BIAB bag? In 10-15 minutes after pulling the bag while waiting for boil to be reached, my BIAB will typically gravity drain another 1/2 liter or so.

 

[BrewingAroundtheRrealm]

Grains will soak up about 1/2qt/lb (~1.04 l/kg)
Without knowing the grist weight, I'm guessing somewhere around 4.5kg? But that doesn't explain 7liter absorption. How long did you drain the BIAB bag? In 10-15 minutes after pulling the bag while waiting for boil to be reached, my BIAB will typically gravity drain another 1/2 liter or so.

I second this. With out knowing the grist weight it's hard to tell where you went wrong. Just taking a guess you would have needed to start with around 15 liters. With a sparge of about 15 liters to get final boil volume.

 

[Cavpilot2000]

Also, in my experience, flaked grains (oats, corn, rice, wheat) will absorb even more than regular barley kernels.

 

[deeve007]

5kg of grains (apologies for not adding that above)

 

[deeve007]

Recipe start volume was 12L, with no specification of sparge volume... so this might be the area that is the biggest issue.

 

[deeve007]

I'm also playing with a small-ish pot (not much longer in current location so not buying another), so the 12L starting volume was about the max that would fit in the pot... but I didn't use anything like 12-15 litres of sparge water I've seen some recommend, so that's my obvious first step to address this.

And due to the small pot it's hard to sparge into this pot, so my thinking now is to buy a plastic bucket that I can move my grain back to once mashing is done, sparge into this plastic bucket while I have the pot heating up to boil, and then add the sparge water into the pot.

Would this work, more or less?

 

[soccerdad]

Just my opinion .. you don't want a lot of heat in a plastic bucket, so make sure the bucket is BPA free, then add cool water to it, then drop your hot grain bag into the cool water to sparge the grains. Also, find a large stainless colander that will fit atop the bucket. Rinse the grains in the bag and set the bag in the colander to drain.

 

[deeve007]

I think I've decided to split my grains in half, and do ~10 litre brews at a time, maybe over two days (no big deal, I work from home), letting the first batch no-chill in my fermenter overnight (yes, have read pros & cons of that versus a cube, gonna give it a try).

That then allows me to start with more water both for mashing and for boil.

 

[RM-MN]

I'm also playing with a small-ish pot (not much longer in current location so not buying another), so the 12L starting volume was about the max that would fit in the pot... but I didn't use anything like 12-15 litres of sparge water I've seen some recommend, so that's my obvious first step to address this.

And due to the small pot it's hard to sparge into this pot, so my thinking now is to buy a plastic bucket that I can move my grain back to once mashing is done, sparge into this plastic bucket while I have the pot heating up to boil, and then add the sparge water into the pot.

Would this work, more or less?

As mentioned, some plastic buckets do non like hot liquids. Make sure your bucket is made from HDPE and is white so you don't leach our unwanted chemicals. This is then an acceptable method.

Make sure you put a lid on your fermenter when you leave the wort overnight to chill as that will keep out the spoilage organisms.

 

[Ninoid]

After god squeeze the BIAB bag I loss 3 liters per 5kg of grain.

 

[deeve007]

So this is the outcome...

Very light for an oatmeal stout, obviously due to the issues mentioned above, but flavour is very decent, if I bought this as a brown ale or similar in a bar I would be reasonably happy with it, so step by step I'm getting somewhere... now just need to sort out my problems above and brew one perfectly!

 

[eric19312]

Just my opinion .. you don't want a lot of heat in a plastic bucket, so make sure the bucket is BPA free, then add cool water to it, then drop your hot grain bag into the cool water to sparge the grains. Also, find a large stainless colander that will fit atop the bucket. Rinse the grains in the bag and set the bag in the colander to drain.

I've heard in the UK there are brewers who boil in plastic buckets. Presumably food grade BPA free of proper type of plastic...

https://www.homebrewtalk.com/forum/threads/plastic-boil-kettles-pail.573330/

 

[eric19312]

I think I've decided to split my grains in half, and do ~10 litre brews at a time, maybe over two days (no big deal, I work from home), letting the first batch no-chill in my fermenter overnight (yes, have read pros & cons of that versus a cube, gonna give it a try).

That then allows me to start with more water both for mashing and for boil.

You could easily chill the first batch, put it in your fermentor and pitch the yeast. Then next day add the new fresh, chilled wort on top. This would have similar effect as doubling your yeast pitch. I've heard plenty of brewers do this on commercial scale. Local guy has a 7 barrel brewhouse and 15 barrel fermenters. He brews first batch and pitches the yeast to give it a head start while he brews second batch. No big deal if second batch is on same day or next.

 

[eric19312]

So this is the outcome...

Very light for an oatmeal stout, obviously due to the issues mentioned above, but flavour is very decent, if I bought this as a brown ale or similar in a bar I would be reasonably happy with it, so step by step I'm getting somewhere... now just need to sort out my problems above and brew one perfectly!

Did you get gravity readings? Given your description about the specialty malts being pulverized I am surprised you didn't get more color out of them not less. Did you stir the mash at all during the mash?

You did retain too much water in your bag so fix that. Hang it longer and give it a squeeze. Should of gotten 7-9 liters out of initial volume.

How did you sparge? I'm not a BIABer but am imagining you would look at the volume you require after first runnings, in your case this would be about 17 liters*. Put the 17 liters of fresh water, hot, cold doesnt really matter in a bucket or kettle, drop the bag into the bucket, open the bag and stir it well so it is well mixed with the sparge water, then hang it again.

*targeting 22 liters pre boil volume, 10% boil off and dumping entire kettle into your fermentor for 20 liters into fermentor. This would be lower number if you got 7-9 liters out of your first step...22-9=11 liters for sparge.

All this assumes you are doing full volume boil not mashing and boiling concentrated and then topping up with water in the fermentor. If you are topping up the math will be different and the topping up water would come out of the calculated sparge volume.

 

[Soulshine2]

Hey guys,

Pretty sure issue is due to my newby-ness, but hopefully something simple to identify the issue...

For my second ever BIAB, did an oatmeal stout 20L batch... so began with 12 litres of water heated up, added grains in bag and left for 90 minutes as per recipe... when removing grains, there was less that 5 litres of water left. I did sparge, but that seems a LOT of water to add/sparge with to get back to the volume it should be, no?

Now one issue that may have caused or impacted on this: My recipe provider, they mill the main grains (pilsen), but not the "speciality" grains. Even after I asked them to do so, they told me to do them just before I mash, but I don't have a mill so not really an option.... but a bit of googling, I saw that some said that you can use a blender. So I tried this, but it did end up with some much finer grains that normal milling would have delivered. So would this have soaked up more water than usual?

(and yes, I need to find another recipe provider who will mill all grains for me...)

buy yourself a mill so that situation doesnt happen again.

 

[deeve007]

You could easily chill the first batch, put it in your fermentor and pitch the yeast. Then next day add the new fresh, chilled wort on top. This would have similar effect as doubling your yeast pitch. I've heard plenty of brewers do this on commercial scale. Local guy has a 7 barrel brewhouse and 15 barrel fermenters. He brews first batch and pitches the yeast to give it a head start while he brews second batch. No big deal if second batch is on same day or next.

This is basically the plan next time. I'm also going to experiment with no-chill cooling for the first 10L batch, leaving the first batch to do so overnight... it is something I'm going to need to master when I head home to Australia early next year, so may as well give it a go now!

 

[deeve007]

buy yourself a mill so that situation doesnt happen again.

Won't be buying any major equipment until I move back home early next year, so learning workarounds right from the get go, used a blender this time for the unmilled grains...

 

[kh54s10]

Australians popularized or even invented the BIAB process. If you haven't nailed the process by the time you move back, I am sure you can find plenty of help when you return home.

Still confused at the loss initially, there shouldn't have been that much absorbed even if you didn't allow it to drain long enough or squeeze out the wort.

But do that, squeeze as much wort out of the grain as possible.

 

[deeve007]

The loss was due to a combination of:
- Not adding grains effectively in the first place causing too much water displacement out of the pot (I lowered already filled grain bag into water, I should have had empty grain bag in water and added grains bit by bit, mixing as I did).
- When removing grains, I didn't sparge well nor leave to drip long enough (or squeeze a little) to get all the wort available. This was pretty clear when I took my bin bag outside later in the day, with how much liquid was present that had drained from the grains I threw away (finding a way to use my spent grains another future project )

Both easily fixable so not super worried I can't address next time...

 

[Saunassa]

I hang mine and after 10 minutes give it quite a few big squeezes and actually lift a corner to disturb the grain and more usually comes out. Then put the bag in a colander over a bucket, open the top of the bag and pour a few gallons of hot water, slowly through the grain and then hang above the pot to drain while I pour the collected wort into the bucket.
One of those ratcheting pulleys from farm supply store hooked on a bike hook in garage truss works great.

 

[deeve007]

I did pretty good my latest batch (an IPA, hit my target OG & volume pretty much spot on!), used more water for sparging, and had a colander over another pot I could leave it in for a while to let as much as possible drain out. Eventually (next year once home) can organise a pully type setup ...etc, but this worked pretty well.