Crush size

[John Kimble]

My grain Mill broke a few batches ago, and I have been using my industrial blender to grind up the grains a few cups at a time. This makes the grain very fine and I never have leftover kernels. That being said a significant amount of the grain filters through the holes in my BIAB metal insert, so I have been putting a mesh brew bag into the metal insert as well. I have a pump recirculating system that pulls water from the bottom during mash phase and recirculates it up to the top of the metal basket. Without the bag in there, the water circulates around the top of the basket and back into the grains that are mashing. With the mesh bag in the basket, the water recirculate underneath the mesh bag and is not pushed forcibly on to the top of the grains.
1. Is the blender an acceptable means of crushing grain, and are there any efficiency issues with that fine of a crush?
2. Will putting the bag in there reduce my efficiency or have any other adverse effects I'm not thinking about?

 

[RM-MN]

My grain Mill broke a few batches ago, and I have been using my industrial blender to grind up the grains a few cups at a time. This makes the grain very fine and I never have leftover kernels. That being said a significant amount of the grain filters through the holes in my BIAB metal insert, so I have been putting a mesh brew bag into the metal insert as well. I have a pump recirculating system that pulls water from the bottom during mash phase and recirculates it up to the top of the metal basket. Without the bag in there, the water circulates around the top of the basket and back into the grains that are mashing. With the mesh bag in the basket, the water recirculate underneath the mesh bag and is not pushed forcibly on to the top of the grains.
1. Is the blender an acceptable means of crushing grain, and are there any efficiency issues with that fine of a crush?
2. Will putting the bag in there reduce my efficiency or have any other adverse effects I'm not thinking about?

Yes you will have efficiency issues with such a fine crush. You can expect the efficiency to be higher than normal. Recirculation will often cause problems with BIAB as the constant flow tends to pick up the fine particles and plug the pores of the bag or basket. That isn't a problem, just turn it off. With that fine milling of the grain you won't have to worry about maintaining the temperature during the hour long mash because conversion will be done so quickly it won't matter. I've seen full conversion as determined by iodine test and by the OG produced in as little as 2 minutes. Don't pull the grains just because conversion is over, it still takes time to extract the flavors. I never recommend less than 30 minutes but the last 25 of that is probably just extracting flavors where the temperature is not critical.

 

[John Kimble]

Awesome, thanks for the answer.
When I use the mesh bag ontop of the metal insert, very very little grist/particulates get into the fermentation vessel. If I don't use the bag there is usually significantly more.
Are there pros and cons either way ?

 

[RM-MN]

Some people get really hung up on getting any grains into their boil but I don't think you will be able to tell the difference when the beer is bottled whether you have clear wort or just a little grain in it.

 

[Mic Carp]

Awesome, thanks for the answer.
When I use the mesh bag ontop of the metal insert, very very little grist/particulates get into the fermentation vessel. If I don't use the bag there is usually significantly more.
Are there pros and cons either way ?

My mash bag is not that fine and i was ending up with a ton of trub, but for less than $10, i got a paint straining bag at Lowes. It has a nice elastic top that fits my fermentation bucket perfectly. It’s around 200 microns and catches most of it. I just put it in the bucket before i xfer then let it hang over the bucket just like my bag does over the kettle. So far I’ve been really happy with the results.