Is there a reason not to apply heat directly to the bottom of the mash tun? I have a three keg brewing system, set up on three gas burners. With a recirc pump. Would an in-line heater be better?
Previously we did a decoction mash, in three steps. Or a single infusion mash, using water heated in another vessel.
Disregard…my false bottom sits a full 3 inches above the kettle bottom allowing for heating without scorching the grain.
BIAB brewers probably all use direct heat while mashing at some point.
When I started AG brewing I used a hotplate under the mash tun. It worked, but you don’t get good heat distribution unless you recirculate. And if you’re going to use a pump to recirculate you’re half way to a HERMS system. That’s the road I traveled, and how I got there.
Charlie
It is fine, but you need to be very careful not to apply too much heat and you need to stir well so you don’t overheat the bottom layer or get wildly non-uniform temperatures. I tried applying a low flame to my BIAB mashes until one day I scorched the bag, which melted onto the bottom of the kettle and ruined the batch. Now I have an electric element in a well-insulated kettle so it can run at very low power. The bag can rest on the heating element with no worries at this low power level.
I have a false bottom and a pump to recirculate. No problems.
For BIAB, I know some guys use something to get the bag off of the bottom. Trivet, colliander (so), or something like those.
That’s the setup we have, false bottom about 3" high, with a recirc pump. This will be a new experience for me as we have always done the recirculating by hand in years past.
Similar to my set up. Some advice:
You need to throttle the pump with a ball valve on the output side. Pulling to hard can compact the grain bed, and you can collapse the false bottom. I know this to be true.
Keep the flame intensity medium low. To high and you can boil the liquid under the false bottom, and I have had the screen forced up, not good!
I have found that the habit of turning on the pump before lighting the flame is a good practice.
Stirring the mash helps equalize the temperature, and also makes the flow better, reducing the possibility of a collapse.
During the mashout rest at 168-170F, I throttle m a little more, let the grain bed settle nicely, and let the wort out of the pump clear.
So it is a balancing act that you will learn.
Hope this helps, have fun.
This^^^^
Or a RIMS system, which is what I use.
Ball valves are notoriously inexact. You can get the same effect by inserting a section of smaller diameter tubing in the flow path to act as a restrictor. Of course it isn’t adjustable, but a section of tubing between 1/4 ID and 3/8 ID will reduce the flow of a March HS-109 pump to about 1 GPM.
Charlie
I use a linear flow control valve on the output of my pump. It is much more accurate than a ball valve. I set it to .155 for the proper flow on my system (I started with 150.5 pictured).
I also look at the flow coming out of the house to gauge what is happening.
Those linear flow valves look nice. Might be an upgrade.
