Recirculation During The Mash (How & Why)


By Darrell Droneburg

Recirculation during mash

Imagine this....You just got all your gear out for a big brew day. You put your recipe into Beerfather/Brewsmith last night, went over it to make sure everything is where you want it. The app tells you that with your grain bill you’ll hit a Post boil gravity of 1.060. Life is good, right? Today’s brew is going to be awesome! Right? 

What if we could make it better?
Homebrewing recirculation meme

Recirculating your mash

You may be asking yourself “What is that and why do I care”. Sit back Padawan, let me explain.
Many of us (myself included) like beer. All kinds of beer. Heck, even bad beer is better than no beer, but why settle for the bad stuff when we can make it better? One of the easiest ways to improve the quality of your wort is by recirculating during your mash. 
So how exactly will recirculation improve your beer? As with most things in home brewing, it depends. Both on how you recirculate, and when you do it. Technique is everything. Generally speaking, recirculation can improve the clarity of your wort and yield more fermentable sugars from your grain bill. 
Clarity is first on the list because it’s the most “obvious” improvement, and you get results almost immediately. There is some debate as to how long you need to recirculate, and like most things for home brewers, it depends on what your goal is. If you’re doing a single mash infusion (more on this and alternatives later) you may benefit most from recirculating the last 15 minutes of your mash time. 
By mashing normally, then recirculating the last 15 minutes you will see an improvement in clarity and get a bit higher efficiency out of your grain, though it may be a nominal improvement. Equipment and your specific process will absolutely have an impact. As previously mentioned, technique is everything. 
Now, to improve that efficiency I personally recirculate for just about my entire mash. Nearly a full 60 minutes in many cases. By recirculating the full length of your mash you’re allowing the enzymes activated to encounter more of the grist, which converts more carbohydrates to fermentable sugars. So, a slow and steady recirculation reduces costs for grain (because you hit the same gravity with less grain) and makes brew day just a little cheaper than it would have been otherwise. Those are the basics of recirculation. 
What are the finer details? The advanced methods? What equipment do you use? How do you do it?
The easiest way to recirculate, and this is the method our 15-minute recirculation folks may use, is to get 2 large pitchers, preferably a gallon or so with a handle on it (remember the wort is hot). Put a hose on the outlet for your mash tun, crack the valve just a bit and allow your wort to trickle out into your pitcher. Hot swap the empty in when the first pitcher is about half full or so. While pitcher 2 is filling slowly, pour the contents of pitcher 1 back into the mash tun. A key point to recirculation is not disrupting the grain bed. Pouring your wort back in too roughly can punch a hole through you grain bed and defeat the purpose of recirculating all together. That said, this is the easiest way to recirculate. Do this for about 15 minutes and you should notice a significant difference in the clarity of the wort that’s draining.
Grain bed during mash
Now if you have a pump, you can do a bit more. With all grain brewing, enzymes are interacting with the grain in the mash tun and converting carbohydrates into sugars. By recirculating through your whole mash, you’re allowing those enzymes to interact with more carbs, resulting in more sugars extracted. Easy peasy right? 
Just like the pitcher method, as the wort is coming back into the mash tun it must be reintroduced gently so we don’t disturb the grain bed, because this would let the wort go through the grain too quickly, not giving the enzymes time to interact with the grain, defeating the whole purpose. Keep an eye on your temps though, they tend to drop while recirculating if you don’t have a RIMs or HERMs set up in place. Temperatures out of range will change the fermentable that are extracted too. Temps too low and you may lose body in the wort, too high and your sugars may be unfermentable. 
Personally, I recirculate with the Blichmann Riptide Pump and the SS Brewtech Recirculation arm with a pieced together HERMs set up to maintain my mash temps, both the pump and arm are available here at Morebeer.com. In the picture below, you can see my pump connected to the valve on the bottom of the mash tun (Orange cooler on the right). It pumps wort into another cooler that is full of hot water, through a stainless coil, and back out into the top of the mash tun. Here is where the SS Brewtech Recirculation arm allows the wort to gently flow back in over the top of the grist. 
The cooler on the left has a stainless coil in it, and the temps are regulated by a sous vide cooker, while not powerful enough to allow for step-mashing, its great for holding a constant temp and then mashing out later. 
Homebrew Mash Tun and Recirculation setup


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