One of the big changes in going from my old system to the Brutus 10 is the use of a plate chiller. Previously, I used an immersion chiller. Before that, I was an ice-bath guy doing extract brews.
The immersion chiller and ice bath have something in common – they cool the entire batch of wort at once.
That's why it was strange switching to a plate chiller where you only cool a portion of the wort at a time.
But then I read the Brutus 10 plans. Surprisingly, Lonnie Mac does not pump through the Therminator in a single pass, but rather recirculates the wort back into the boil kettle until it reaches pitching temps. He doesn't say in the plans why he does it this way, but I found this HomebrewTalk thread where he explains it:
“It works like a charm and there are MANY reasons for doing it this way…I reach the DMS Gspot in under 3 minutes and lager temps in under 20… That is all that matters. Trub is in the pot and sweet cold wort in the fermenter.”
There is also Jamil's famous Whirlpool/Immersion chiller which follows the same principles as Lonnie's plate chiller method.
So that got me thinking about recirculation instead of a single pass. I ended up trying both techniques. I'll tell you later which one I prefer, but first let's look at the advantages and disadvantages of each:
Single Pass Chilling
This is the most common way to operate a plate chiller. After the boil (or whirlpool), you drain from the kettle, through the plate chiller, and into the fermenter.
Advantages: You can cool the wort more quickly this way. How long does it take to cool? As long as it takes to empty your kettle. You can even use gravity to feed through the chiller.
Disadvantages: Accurate temperature control is more difficult. If your ground water is too warm, you will have to pre-chill it, pump ice-water, or cool the fermenter to pitching temperatures after the fact. Also, the cold break gets carried over to the fermenter.
This is an alternative way to operate the plate chiller. Instead of running the wort directly into the fermenter, you recirculate back into the boil kettle until you reach you desired temperature. Then you redirect the flow into the fermenter.
Advantages: Easier temperature control. You cool the entire batch at once, locking in late addition hop flavor and aroma. Possible reduction in DMS* (see below).
Disadvantages: Takes longer than single pass cooling. It requires a pump to return the wort to the boil kettle.
*This is a debated topic so I'm not ready to say it's a sure thing. Here is what Jamil says about DMS and why his whirlpool chiller solves the problem
“DMS is often described as a cooked corn aroma that often plagues lager brewers. The thing is, the lighter pilsner malts contain more SMM (S-Methylmethionine), which gets hydrolyzed to DMS during the boil. Yes, this gets driven off, but unless you're doing 100 minute or longer boils, there is still some SMM left behind. The neat thing is, if you can get the temperature of the wort below 140F (60C), then SMM will not be converted to DMS. The whirlpool immersion chiller will drop the temp of the wort below 140F (60C) very quickly, resulting in far less DMS in the finished beer. On the other hand, counter flow and plate chillers continue to hydrolyze SMM into DMS while sitting there at near boiling. “
What do I do?
In 5 batches on my Brutus 10 I've done single pass twice and recirculation three times. I prefer recirculation so I'm going to stick with that until I find a reason to abandon it. Let me explain why I like it.
The big advantage of single pass chilling is the time savings, but with recirculation I am able to cool the wort from boiling to 65°F in 15 minutes. Given the other advantages, that is plenty fast enough to go with this method.
The single pass method took 10 minutes. I couldn't run the pump wide open because the wort wouldn't cool enough. It would have been quicker if I pre-chilled the cooling water.
My method with recirculating is to knock the wort down to about 140°F with a garden hose. Then I disconnect the garden hose and connect my HLT which is filled with ice water. I use the second pump to recirculate the ice water through the chiller and I hit the 60's in no time. This isn't a new idea – it's the one from Lonnie's original Brutus 10 plans.
With the single-pass method, the temperature control was a real downside. It's been a HOT summer in Denver and my ground water is around 70°F. I like to pitch the yeast right away, so bringing the wort down to pitching temps after the fact isn't going to be a long term solution. Sure I could pre-chill the water or use ice water, but the process is still too variable. Even with an inline thermometer it was difficult to get the exact right temperature out of the plate chiller.
I like to know exactly what the wort temp is when I drain into the fermenter and recirculation gives me that level of control. Plus I can leave the cold break (at least most of it) behind in the kettle. The 15 minute chill time is also in 90°F+ heat, so in the winter it will be even quicker.
So why not use an Immersion Chiller?
Well for one I already bought the Therminator ; )
Honestly though, I do love this thing. I mean look how compact it is. With limited space, that's a HUGE deal for me. My old 50′ immersion chiller took up 5 times the space.
But don't think that a plate chiller is “a step up” from an immersion chiller. In fact, there is a shift back to using them due in a large part to Jamil's whirlpool chiller. Some people are even switching from a plate chiller to an immersion chiller.
My method is in no way set in stone and with limited B10 brews under my belt, things could change. I'd love to discuss this more in the comments, especially with fellow plate chiller owners.
Let's hear from you.