No need for PID recirc with BIAB?

[badmajon]

If you feel the need to do the PID controlled recirculation you need to keep the bag off the element as direct contact will burn a hole. My point was that if your grains are milled fine, the time for conversion will be so short that the temperature drop will be so little that adding heat will be pointless. With my system I've found that conversion only takes about 3 minutes. I continue to mash for 10 minutes just to be sure that the beta amylase has time to complete. That's all.

and...

The last batch I did took me 2 hours, ten minutes from starting to bring equipment up from the basement to having it all cleaned and put away except for the items that I washed and weren't quite dry yet. That included weighing and milling the grain. With a bigger heating unit I suspect that 2 hours would be possible. I did a no-chill so I didn't have to wait for the wort to cool, dumped the boiling hot liquid into the fermenter bucket and pitched when it cooled.

That kind of shoots a hole in the PID controller. I'm sorry.

RM-MN is saying that you don't need a PID controller at all when you do BIAB since it converts so fast and therefore there is so little heat loss. This seems too good to be true. Thoughts?

 

[jeffmeh]

Interesting. With a 13-minute mash one would certainly have to do an iodine test, or prefer sweeter brews.

As a propane BIAB brewer, I usually just cover the kettle with a blanket and leave it for 60 minutes. I sometimes add a few blasts of flame in colder weather and stir. If I were building an e-BIAB I would recirculate, but it is certainly not necessary.

 

[badmajon]

It just seems like hitting the right temp would be a total hit or miss affair. My main problem brewing right now using a keggle/igloo cooler with false bottom setup is I rarely can hit my desired mash temp. It usually works out fine, but it's totally unpredictable and certainly unrepeatable. I just dump in my mash in water, stir, and pray... trying to not have to do that anymore, hence why the electric PID control seemed like a way to upgrade.

 

[Bartp]

Today's malts are highly modified and yes, the enzymatic conversion is much quicker, but I don't think it's that quick! I did a test a while ago where I was measuring gravity of my recirc every 5 min, and I was getting a worthwhile extraction for up to 45 mins. Also, even if you extract sugars in 3 min, you won't extract the flavor and aroma from the grain.

Someone should experiment with a grain tea for 3 min and 60 min and see which one tastes better (or fuller).

 

[badmajon]

Thanks for the feedback. I bought a BIAB-bag and I will be testing it soon. At least with BIAB if I screw up the strike temp, I can blast it with some heat. My biggest problem with the traditional method was that I would strike too low, and I'd have grain soaking in the mid-140s. Bad conversion and weak, thin taste in the finished product.

My last failure was 10 gallons of what was supposed to be a pilsner, mashed in and only hit 146. I got terrible conversion, about 62-63%. Then I added almost 2 lbs of corn sugar to give it some gravity and it tastes pretty bad I have to say. I'm hoping the nasty sugar twang will fade as it ages.

 

[Woodbrews]

I do 5 gallon eBIAB with recirculation, on the theory that recirculation helps to avoid temperature stratification in the mash. With recirculation, I have observed at most a 1 to 2 degree differential between the top of the kettle and the bottom where the probe is (under the bag). During a one-hour mash, my element comes on once or twice at most, and then only for a few seconds. My bag sits directly on the element and I've never had a scorching problem, even with a large grain bill (> 12 lbs). I mash with the lid on and with no insulation of any kind on the kettle (an 11-gallon Bayou Classic).

 

[aamcle]

I have a 50litre pot that I use for recirculating BIAB, I have the bag in a basket to keep it off the sides and the element and I recirculate throughout the mash.
After insulating all the way from the tap to the spray head were the mash is returned I got down to just 1°C difference top to bottom, it may well be less but I don't have thermometers good enough to be sure.

Atb. Aamcle

 

[Bartp]

Also, PID is also good for hitting strike temps. I usually overshoot my temps by about 5 degrees, meaning I'll set the PID to 159 for 154 degree mash. Dump my grain in, dial down the PID to 154, by the time I'm done steering the mash is at proper temp. No need to do hard calculations to hit the temps "just right". I usually mash with 15 gallons and about 25-30lb of grain.

Also PID is a fantastic tool for step infusion.