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Brewing with The Grainfather, Part 2 - The Boil

In Part 1 of this series, I explained a little about iMake's The Grainfather RIMS brewing system, walked through the mashing and sparging steps, and shared some recommendations.  In this post, we're going to talk about the boiling and chilling steps.

Boiling Wort with The Grainfather

Being a 120V 1600-watt electric device with a standard US 3-prong electrical plug, you can use The Grainfather indoors provided you aren't in such an enclosed environment that the escaping steam will cause you problems.  I'm able to brew in my basement without any need for fans or other ventilation.  In a small apartment kitchen, I can imagine that the steam might condense on the walls or ceiling and cause an issue - but that's only speculation on my part.

When you've finished the mashing and sparging effort, starting the boil is a simple activity.  You remove the grain basket from the kettle, then switch the heating element mode switch from Mash to Normal (if it's not already set that way).

Heating Element Mode Switch
With the heating element in Normal mode, you'll switch the temperature controller to boil.

The switch in the upper-right of the controller
with the I and II on it) switches The Grainfather
into Boil mode (II on the switch)
Now, you'll watch the temperature display on the controller to see when it reaches approximately 212F (the boiling point).  The Grainfather's boil is a rolling boil, but depending on other heating elements you may have used in the past, you may note that it's not a particularly turbulent boil.  Despite that, I've had no issues with the beer coming from The Grainfather so I don't see the lack of an overly turbulent boil as an issue.

If you're not planning to babysit The Grainfather during the boil, I recommend two things.  First, get some Fermcap-S or a similar product to break down the foam on the top of the kettle.  If you don't do this, boil-over is a very real possibility as the foam rises during the early part of the boil.  This doesn't happen for me with a few drops of Fermcap-S.

The other recommendation is to at least check the temperature on the boil every 10 minutes or so.  If you ended up with a lot of residue flowing out of the grain bed into the bottle of the kettle, there is a very real chance that you'll end up with scorching.  If that happens, The Grainfather's anti-scorch protection will kick in and cut off the electricity to the heating element.  Your wort will start cooling down and stop boiling, which can mess up your beer.  Attaching the recirculating arm and turning on the pump can reduce (but not eliminate) the chances of this occurring.

The Grainfather's iOS and Android apps contain timer functionality that will help you schedule the addition of hops, spices, adjuncts, etc., into the boil.

Wort chiller attached to the kettle and
ready to recirculate boiling wort
In the last 5-10 minutes of the boil, you'll need to attach the counterflow wort chiller to The Grainfather and recirculate boiling wort through the chiller and back into the kettle.  The purpose of this is to sterilize the wort chiller and reduce the chance of infection when you pump the wort into your fermenter after the boil.

Hot wort recirculating into the kettle
Once the boil is complete, you're ready to begin chilling the wort and pumping it into your fermenter.


The Grainfather includes a counterflow wort chiller.  This chiller is hands-down my favorite feature of The Grainfather.  With a tap water temperature of 68 degrees, boiling wort will come out the other end of the chiller in the upper 70's.  With colder tap water like we see in the winter here in Ohio (52F the last time I measured it), wort comes out in the mid-to-upper 60s.  This makes for practically instant chilling!  My immersion chiller on its best day managed to chill 5 gallons in 40 minutes.  The Grainfather's counterflow chiller does that in about 15 minutes (and the wort is pumped into the fermenter in the process, where I had to perform a gravity transfer with my immersion chiller and kettle).

Sometimes, the wort you get out of the chiller isn't cool enough for the yeast you want to pitch.  When this happens (and although iMake doesn't really encourage it), you can recirculate the wort back into the kettle until the kettle temperature drops significantly.  Then you shut off the pump, move the hose to the fermenter, and pump into the fermenter.  During the summer, wort came out of the chiller at about 78F, which was too hot for the yeast I was using.  I recirculated the wort into the kettle until the kettle temperature hit 130F, then began pumping into the fermenter.  This time around, my wort temperature was more like 66F, which my yeast tolerated well.


I really didn't start measuring my efficiency with The Grainfather until the last batch I did.  On that batch, I measured my pre-boil efficiency at 77.43%.  That's right in the ballpark for most published recipes which are based on a 75% efficiency.  So far, iodine tests have always indicated that conversion was complete (or as complete as the test can measure) at the end of mashing.

Comments and Thoughts on Boiling and Chilling

Provided you haven't gotten too much sediment into the bottom of the kettle during mashing, the boiling and chilling steps with The Grainfather are usually the easiest parts of brewing with it.  The boil is rolling but not dangerously so.  The chiller is fast and efficient.

Where you can run into problems is with sediment in the kettle, or with adjuncts added during the boil which congeal in the bottom of the kettle and cause scorching.  If you're going to use malt extract, candi sugar or syrup, honey, or other thick sugary substances in The Grainfather, I recommend dissolving these in some hot water or wort outside The Grainfather before adding them.  This will reduce the chances of these substances accumulating on the kettle near the heating element where they will trigger the thermal cut-out switch and scorch protection.  (Dry extract can usually be added directly to the kettle without causing scorching since it tends to float when it doesn't dissolve.)

A problem I'm still wrestling with is that of reaching my desired post-boil gravity.  The biggest issue for me in this area is to avoid over-bittering the beer.  As you know, the longer you boil wort with hops in it, the more bitter the beer will become.  If you reach the end of a 60-minute or 90-minute boil and your gravity is too low (and your volume too high), the best solution is to remove the hops and continue boiling until you reach the gravity target.  I've been using hops bags to reduce sediment in the kettle.  Invariably, these fall to the bottom of the kettle near the end of the boil and I can't retrieve them.  Not wanting to over-bitter my beer, I usually have to just settle for the lower gravity or toss in an adjunct to raise the gravity.  I'm planning to build or buy a "hop spider" before I brew my next batch, so that I can remove the hops if I need to extend the boil time.  This should allow me to hit my gravity target without winding up with an over-bittered Tripel, Dubbel, or similar beer.


  1. Just read this for tips about the counterflow chiller, I didn't realize I should run it through slowly. I've been recirculating the wort to get it down in temp at full flow, oops.

    But I saw you had an issue getting the hop bags out before chilling if you needed to extend your boil. Why don't you just use a long paddle to pull it out? This is what I've been doing, though generally the hop bag is floating... if it isn't I just use my long skinny paddle similar to the one in the grainfather videos to reach in and kind of scoop the hop bag out. It's as easy as pie, never had any issues getting it out and the boiling wort is sanitizing everything.

  2. I am very happy to discover your post as it will become on top in my collection of favorite blogs to visit.


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