Brew bag and a half-sparge

[LickingGoatBrothersBrewin]

I am a little limited on equipment (size) while I am temporary out of the US, and I want to use my brew bag to fill in my equipment gaps. Let me know if this plan is crazy.

Batch size target is 20 L.
Style is Franconian Bockbier
Grain quantity is just over 6 kg.
My electric kettle can only hold safely 30 L of liquid.

My plan is to start with about 20 L in the kettle and bring the water temp up to about 63*C (at this point about 18 L is still available in the kettle). Then place the brew bag in the kettle and pour my milled grains into the bag. This should drop the temp down to about 60*C, but I can maintain this target 60*C temp easily with the electric kettle. Mash for about 45 minutes, then step up to 72*C for about 15 minutes, and then mash out at 76*C. At this point I want to just lift the bag and leave behind the pre-wort in the kettle. Then I want to swing the bag over and down into a 25 L lauter tun bucket (thin-walled, not insulated) which has a cake cooling rack in the bottom to keep the bag off the exit valve hole. I will then add 12-14 L of 76*C sparge water to the bag/grains/tun and stir the grains for a minute or two. Then allow the grains to settle and steep some more for about 10 minutes, and finally open the tun valve and let this second pre-wort into the already heating first pre-wort for the boil.

I am hoping this half sparge step in the bucket will squeegee the rest of the sugars off the grains, instead of just pouring water over the bag as it hangs above the brew kettle.

Am I way off here? Too complex?

 

[McKnuckle]

Sounds great. It's essentially what we call a dunk sparge, which I agree is more effective than a pour-over sparge. Alternately, you can leverage the "dunk" for your mash out if you like, or for a higher temperature rest if the mash sequence requires it. Perform the main mash in the kettle. Dunk sparge in water of whatever temperature is required to achieve the next rest temperature, then drain to kettle and boil.

 

[doug293cz]

When you do the sparge, the stirring is the most important part. Stir aggressively for 3 - 5 minutes, and then just drain. The dwell will get you nothing if you have already done a mash out.

Sparges only get out most of the sugar retained in the grain after the initial run off. You can never get all the sugars (unless you rinse with an infinite amount of water.) The chart below shows lauter efficiency for a variety of conditions. 100% - lauter efficiency is the percentage of sugar left in the grain.



Brew on

 

[LickingGoatBrothersBrewin]

Thanks for the quick feedback. I finally got my brew bag through import/customs today. 6.50€ import fees on a $30 mesh sack.... Group brew day is coming up soon. Probably 3 or 4 kettles going at once with 3 or 4 different regional recipes. Gonna be a good fall!

 

[LickingGoatBrothersBrewin]

Follow-up question due to another equipment restriction:
What is the consensus on rinsing/sparging with non-heated (room trmp) water?

 

[doug293cz]

Follow-up question due to another equipment restriction:
What is the consensus on rinsing/sparging with non-heated (room trmp) water?

Results are equivalent to hot water sparging. The exception is if your mash conversion is incomplete prior to sparge AND you did not do a mash out. In that case a hot water sparge can allow some additional conversion during the sparge step, thus increasing overall efficiency. Cold water sparging will increase the time required to heat to a boil.

Brew on

 

[LickingGoatBrothersBrewin]

Results are equivalent to hot water sparging. The exception is if your mash conversion is incomplete prior to sparge AND you did not do a mash out. In that case a hot water sparge can allow some additional conversion during the sparge step, thus increasing overall efficiency. Cold water sparging will increase the time required to heat to a boil.



Brew on

Wow, that was a great study. Mash out is planned, so I will go with room temp water. It will increase the time to reach the boil, but I don't think too much time will be lost. Thanks for the great feedback.

 

[Parrothead01]

I mash with 8 gallons and then pour a few more room temp gallons over the bag and into the kettle. I figure that whatever I get out of it is better than just pouring the water in. I started doing it because I was making a high gravity beer and couldn’t fit it all in at once. Now I do it all the time.