BIAB mashing question

Want to start BIAB soon. Think I have the basic process down from reading various threads, but have a question on mashing. What is the difference, if any, between heating water to desired strike temp, then adding grains vs. adding grains to cold waterand then bringing up water temp to desired mash temp?

Seems the later would make it easier to hit mash temp, as you just turn off burner when desired temp is achieved.

For one thing, it's hard to directly heat your mash without scalding your grain. The other issue is that the grain would be exposed to all the temp changes along the way. I'm not sure exactly how this would affect your final product, but I'm pretty sure it would.

It may work, and you might make beer... you just might not like the final product

Thanks HItransplant. Seems like that's the way most folks do it. Was looking at the BIAB wiki and it summarized the process as
In layman’s terms, BIAB can be summarized as follows: You put a nylon bag in a big pot of water, pour in some grain, heat it to a specific temperature and hold it at that temperature for 90 minutes. At the end of the 90 minutes, the bag holding the grain is removed and then the remaining liquid (hot liquor) is boiled for 90 minutes with hops being added at several stages during the boil. After the boil, the resulting wort is cooled rapidly and the yeast pitched. All other stages of the brewing process should be familiar to those who have done some kit brews.

That's why I wasn't sure if it mattered. Makes sense that bringing the grain up through different temps might somehow effect it though.

The major problem with putting the grain in cold water and heating to mash temp is the mixing. It is really hard to get an even temperature when you have the grains in the water. Even putting the grain in the water that is heated to strike temperature will give you hot and cold spots in the grain unless you stir like a demon. You'll have to choose where the thermometer goes and then hope it is somewhere close to the correct temperature when you turn the heat off.

I had a batch that the temperature fell farther than I intended so I turned the burner on low to bring it back up. After 10 minutes the temperature hadn't changed so I turned the burner off, a bit discouraged. 10 minutes later the temperature was too hot! Yes it takes a long time for the heat to migrate through the grain.

The only difference with BIAB is the bag. Otherwise it's the same as any other mashing technique.

Deathbrewer has some awesome threads on BIAB techniques. Oh, and there is a BIAB forum somewhere online.

Good luck and happy brewing.

If you put the grain in first, then heat up the water you'll end up ramping through all the various rest stages, when really you just want to jump straight to a beta amylase rest.

A fairly safe thing to do is heat your water to about your mash temperature, put your bag in (this will cool the water), then heat up to about 2-3F more than your mash temperature.

Then dump your grain, agitate with a potato masher and apply heat until you hit your mash temp again. You should be pretty close. After a few minutes agitation the mash should be a uniform temperature and pretty close. I would normally heat slightly warmer than I need, rather than cooler

And then you insulate and walk away.

If you want you can apply more heat at 15 or 30 minute intervals... up to you.

If you want you can then heatup to mashout temp (172F), and pull the bag.

If you are going to be applying heat while you have the bag+grain in there, then it is a good idea to use a cake rack or some other solution to raise the bag off the bottom of your pot, just a little bit.

If you actually pull the bag out to raise the temperature, the temperature will fall very quickly when you lower the now cooled bag back in!

The website for that "biab forum" is http://biabrewer.info

Thanks all for the replies. As soon as I kill my last couple extraxt kits, going to definately try BIAB. My pot is only a 7.5 gallon turkey fryer, so may not be able to do big beers, but really looking forward to trying this. I can see the next steps now...... bulk grains and hops...a grain mill...kegging...

I use a turkey fryer and found that with 6 1/2 gallons of water and a moderate grain bill I was right to the top. Since that first experience, I've modified my procedure and start with 5 gallons of water in the turkey fryer and do the mash, then use colder water to rinse out the grain bag to where the grain is cooler so I can squeeze all the sweet wort possible from the grain bag, trying to get that 6 1/2 gallons of wort in the turkey fryer before the boil starts. Watch closely for boilover at this point and add the hops after the hot break settles.