First BIAB Brew Mash Kettle Question

[danielofthedale]

Doing my first all-grain brew this week and I am very excited. I have a question about holding my mash temp. I have a SS Kettle and will be mashing at 158* with 13# of grain with a 1.5qt/lb. I am planning on warming the strike water to around 170-172*. Will the kettle hold the desired mash temp for the whole hour of the mash or will I need do something to keep the temp stable? Would wraping in a blanket do the job? I really don't want to keep the kettle on the burner just to really avoid any chance of scorching the brew bag. Thanks for any advice and any other BIAB tips would be great too if you have any.

 

[enkamania]

Blanket or sleeping bag would work. I use water heater insulation, with a blanket over the top

 

[ryansanders]

If you can fit it in your oven, you maybe be able to preheat it to 170 and have the kettle live in there for an hour.

 

[RM-MN]

If you have a sufficiently large pot, use the full volume of water for your mash or at least close to it. With that volume of water and grains at room temperature your strike water will only need to be about 162 to get the 158 (that seems pretty high too) mash temp. If your grains are milled very fine, your mash will be done in less than half an hour so plan on a 30 minute mash. With the full volume of water and that shorter mash time, your pot (sitting inside the house or a sheltered area) will lose less than a degree. Not enough to worry about.

When the mash is over, pull the bag out immediately and crank up the heat. Collect as much wort as you can from that bag of grains, squeezing it like it owes you beer. If your volume collected is less than you expect for pre-boil, pour a little cold water into the bag of grains and squeeze it out again. That little water will raise your efficiency too.

 

[Foosier]

+1 to mashing in with the full volume. With more water you create a much larger thermal mass which takes a much longer time to cool. check out the BIAB stickies for best practices. I recommend the SIMPLE BIAB CALCULATOR. Search for it on-line. Works like a champ.

As far as maintaining your temp. I use a moving blanket and wrap my kettle, in place, on top of my burner. (Obviously, the burner is off during the mash.) Blankets, sleeping bags and coats have also been used by many successfully.

One key item I would mention. You really don't want to try and move your kettle when it is full of the mash or any other hot liquid. You are asking for a big nasty spill and at best a hell of a mess and at worst you can be hurt badly. I moved mine the first time and I almost killed my back. Just kill the flame and leave it on the burner stand. Wrap the kettle and walk away. The mash is a good time to get set up for the boil, get some food, more homebrews, chores, etc... to avoid scorching your bag just remember one rule: If the flame is on, you need to stir the wort. The bag scorches when it is pinned by the grain against the kettle. If the wort circulates, this can not happen.

Good luck with your brew!

 

[Epimetheus]

If you have a sufficiently large pot, use the full volume of water for your mash or at least close to it.

Thermal mass. That is what the Aussies suggest on a BIAB forum. They report losses of 1 to 2 degrees Celsius (2 to 4 degrees Fahrenheit) for an uninsulated full volume BIAB. That assumes a volume for a 5 gallon batch, which can be 8 to 11 gallons.

I work with smaller volumes and the temp drop was not acceptable. Eventually, I settled on wrapping it with Reflectix aluminized bubble-wrap and holding it on with aluminum duct tape. True ducT tape, not ducK. This Reflectix will melt over an enthusiastic propane burner.

I mash and boil BIAB on a glass topped electric stove, the largest element is 2000W. The pot is 8 gallons so a full volume mash BIAB is not possible for 5 gallons. And the stove cannot boil 7 gallons without insulation. (side note: a 1500W heatstick does wonders)

I tried the old jacket and blanket route. Occasionally the jacket shell or blankie would touch something hot and melt.

Tip: DON'T MESS WITH THE MASH!
Calculate the strike temp for BIAB, add the grains and stir, take a final temp reading and GO AWAY.

I have screwed up mashes when I fiddle with adding heat, then ice, more heat. Just let the enzymes work. They are good from 160F down to 146F or so. Whenever I have left it alone, it has worked a treat.

 

[danielofthedale]

Thanks for the great advice! My pot is 7 gallons so can't do a full volume but I am doing as much as I can.