Article
Indoor Induction Heat
Brewers tolerate a lot of adversity for the sake of their beer. We are subjected to adverse elements; who among us hasn’t ended the brew day by patching up cut fingers that numbly tried to attach a small fitting to a razor-sharp thread in sub-zero temperatures? (Well, at least those of us who brew in colder temperatures?) As I was writing this article, a friend called and told me he had to put off brewing for a bit because his outdoor water line had frozen solid. And then there’s the fact that we’re often cranking up an industrial-strength jet burner that would melt the face off of the Stay Puft Marshmallow Man in about fifteen seconds flat, to say nothing of what it feels like to stand next to a floor-mounted flamethrower on a blazing summer day. What would we give to brew in better conditions? Induction is a highly efficient, safe, and cost-effective source of brewing heat that can be operated indoors and has very few drawbacks. My love for induction was based on the fact that it addresses not only the challenges of traditional outdoor jet burner systems, but also the limitations of other indoor options. It is an electric-based heat source that generates no heat, a low-output heat source that can nevertheless boil 5 gallons (19 L), and it requires induction-compatible equipment that most of us are already using without knowing it.
Let me first say that I have nothing to gain by writing this article. I do not manufacture induction elements. I hold no stock in mining interests that would see a boost in demand for metals if induction takes off among homebrewers. I do not represent a cookware company that wants you to buy a new pot (and you may not even need to — I’ll explain later). I’m just a guy who hates brewing in variable conditions because it creates variations in the beer, and I wanted to find a better way. I would also like to add that I am not a metallurgist or physicist; the science behind induction is something I understand in much the same way that I understand brain surgery — I’m aware that it exists and the basic mechanics are clear to me, but I’m not in a position to do it myself. What does this mean about induction? Well, first, that I objectively believe it to be an excellent alternative source of brewing heat. It also means that you don’t need to be technologically savvy to use it. Let’s get into it, and we’ll see if you agree.
The Magic of Induction
When exposed to induction for the first time, many people find it nearly miraculous. A pan placed half-on/half-off of an induction element has an egg cracked into it; the half of the egg on the pan over the element begins to sizzle, the other half lays inert and covered in salmonella. What sort of wizardry is this?
Induction heat elements work by generating an electric current, which creates fluctuating magnetic fields. A conductor (in this case, your steel boil kettle) reacts to those magnetic fields, creating additional currents and smaller additional magnetic fields. All of this pushing and pulling of molecules within the pot creates friction within the metal itself, and friction creates heat. What this means is that an induction element is not a heating element — it’s your pot that’s doing the heating. The element is just making your POT hot, and undergoes no thermal heat production of its own, which means that induction is near-100% efficient. The heat level is controlled by increasing or decreasing the wattage passing through the induction element.
There are two key components needed for this process to work, though. One, obviously, is electricity. The good news here is that you can get sufficient power out of a standard 120-volt wall outlet to boil wort. The second is that your kettle must be made of a ferromagnetic material — it must have certain amount of iron in it to react appropriately to the magnetic fields. Most types of stainless steel are induction-compatible (but not all types). Aluminum, copper, and some other steel blends will not work with induction elements. The easiest way to tell if your equipment will work on induction burners is to place a magnet on the bottom of your pot. If the magnet sticks, it will work. First, however, let’s talk about why you should be using induction heat, and then we’ll look at any new or different equipment needs, including where to get your own induction element.
Why Use Induction?
What’s good about induction? Well, first off, it will save you money. My 1800W induction element was actually a few dollars cheaper than a floor burner, but that’s not where the real savings are. For a hypothetical 5-gallon (19-L) batch of beer with an ingredient cost of $30 and about 2.5 hours of total “heating” time, propane will add roughly 20% (about $6 from a $15 tank fill, excluding the cost of purchasing the tank) to the cost of producing that batch of beer. If you’re one of the lucky few who have a dedicated natural gas line, you’ll only add 8–10% (about $3, excluding the cost of installation of the line) to your cost per batch. Induction, however, is practically free: running my induction element at full-bore adds less than one percent to my beer production costs (about 20 cents per batch, and all I need is an existing wall outlet). Induction is nearly 100% efficient, but most of the heat from a jet burner is blowing up the sides of the pot, not getting into your wort. In other words, by comparison to using a propane or liquid natural gas (LNG) burner, an induction element will essentially pay for itself in about 25 batches. (The savings is increased even further if you factor in the price of a ventilation hood if you want to use LNG indoors. No ventilation is required for induction.)
Second, induction is safe. There is no hot element to worry about, just a hot pot. No chance of fire from a tipped element. No worry about improper ventilation causing a carbon monoxide (CO) buildup. No drifting paper towels to catch flame, blow across the driveway, and burn your house down (OK, that last one is a stretch, but it’s the one my wife raised when I brought home my jet burner). And since there’s no flame or hot resistance element, you can thoroughly wrap your kettle to avoid any burns from hot kettle surfaces. The only real dangers left once you switch to induction are those that you cannot eliminate from brewing, namely steam coming from the pot and the presence of boiling liquid. It just doesn’t get much safer than that.
The third advantage that I briefly mentioned earlier is that induction creates no special ventilation requirements, which means that it can be done anywhere, particularly indoors. This means that in December you can be brewing in your warm kitchen, in full view of a 50” HDTV showing the latest Dallas Cowboys collapse, as the winds and snow howl outside. It also means you don’t have to contend with the winds that hurt your boil and attack the repeatability of your process. Now, while the same is true of other electric or natural gas elements (particularly those on your range), their power output is not usually enough for a full-wort boil on a 5-gallon (19-L) batch. And while there are those who use electric elements or heat sticks of sufficient power to boil a full batch, there is a substantial DIY component to such systems, and they also have the potential to add flavor and/or aroma elements as a result of the exposure of the wort to intensely-focused heat. Induction requires no special outlets, spreads heat evenly and cuts down the chance of scorching (cleaning your pot has never been easier), and is perception-neutral.
A fourth advantage to induction brewing is that it is incredibly quiet. Instead of the sound of jet engines that you get from using gas burners, you can fill the sound up in your homebrewery with something a little more pleasant — like jazz music or the baseball game.
So why do it? A better question might be, “why WOULDN’T you do it?” Well, there are a few reasons . . .
Limitations to Induction
No method is perfect, and induction does suffer from some drawbacks. None are insurmountable, but they do need to be dealt with if you’re going to be happy with your new system. They fall into four categories: power, temperature, time, and equipment.
There is an upper limit to the amount of power that a 120V wall outlet can deliver, and it tops out at about 2000 watts. That translates into only 6,824 BTUs (equivalent) coming from your 1800W induction element; when stacked up against the 70,000-plus BTUs you get from some jet burners, the induction element looks like a 90-pound weakling by comparison. There are two things that keep this from being a deal breaker, though. First, nearly all of that 6,824 BTUs is going into your wort, so our 90-pound weakling is more like the WBA flyweight boxing champ: there’s not much there, but what IS there packs a punch. It is more than enough to boil 5 gallons (19 L), with only minimal insulation to maximize your efficiency. Second, we aren’t necessarily limited to just 120 volts — many homes have 240 volt outlets available, and if they don’t installing one is a quick job by a certified electrician, who can put one just about anywhere you’d want. That increase in the power budget means you can invest in a 3000W-plus induction element, which should be enough power even for those who like their 10-gallon (38-L) (and larger) batches. The one consideration to keep in mind when scaling up the size of your induction element this way, however, is that they do increase in price.
Now, just what kind of a boil will you get? Admittedly, at 1800 watts you will not get the leaping, roiling, violent boil you can achieve with a jet burner — but so what? If the goal is to break the surface of the liquid and allow for off-gassing of compounds we don’t want in the beer, then a little bubbling and rippling is all that’s required. If the goal is to get good convection to aid in that process, then an amount of heat sufficient to accomplish that movement is all that’s required. Induction gives us both. Since the boil is not as active, there’s also less risk of a boil-over. And while not an impressive-looking boil, it adds one additional benefit: evaporation rates should drop, saving you wort and making for a more-pleasant (and less rainforest-like) indoor brewing experience. My evaporation rate is just under 9% (compared to an informal survey of reported rates by other brewers of around 15%). It’s not a “pretty” boil, but it means more beer and less cleaning. That’s a win in my book. The key with all of this is Dimethyl Sulfide (DMS) removal and break formation. Commercial brewers typically evaporate 6–10% during the boil, so 9% is right in the norm. The proof in the pudding is flavor and stability. A “rolling boil” is subject to interpretation; evaporation rate is measurable. If you prefer a more vigorous boil, however, that is easily remedied by using a higher-power induction element.
If there’s one consistent complaint I’ve heard from those considering switching to induction, it’s about time. Induction does not heat wort at speeds anything like the meteoric increases in temperature you get out of a jet burner, but with proper planning it is no slower. It’s more a question of anticipation, and doing it the same way every time, which is hardly the worst thing to promote in your brewing process. I’ll get into more later on in the “how-to” section of this story, but for now, suffice it to say that from the time I fire up my mash tun pre-heating water to the final towel-gathering after cleanup, my process for a 4.5-gallon (17-L) all-grain batch-sparged beer clocks in at just under four hours.
Then there’s equipment. As mentioned previously, induction elements themselves are not prohibitively ex-pensive. You can purchase an 1800W induction element from most restaurant supply stores for under $200. Instead of the brand name, focus on two things: element diameter and construction. You want the widest possible diameter to improve your performance: too small an element and you’ll end up with a narrow pillar of heated wort that gives up too much energy to the cooler wort around it to maintain a proper boil. My cooker has a 9-inch-diameter (23-cm) element, and that seems sufficient. It also has a steel case and a thick glass surface, which are easy to clean and easily holds the 45-or-so pounds (~20 kg) of pot and liquid that rest on it. Use your best judgment — and if you find a great deal on an induction cooker that’s a little flimsy, there are plans out there for simple support and framing systems to share the load. One of the cool things about induction is that the pot doesn’t actually need to contact the surface of the element — it just needs to be nearby!
When it comes to kettles, your focus should not just be on materials, it should also be on geometry. Use the magnet test on your brew pots described on page 30 to determine if your equipment is induction-compatible. If the magnet holds, you’re good to go! This doesn’t apply only to “specialty” pots with some kind of “induction-approved” logo on them and a hefty price tag; my 5-gallon (19-L) kettle came from Target and set me back only $47. One drilled hole and a weldless fitting later and I had a ported induction-capable boil kettle. Obviously, you need a pot that will heat, but pot geometry is nearly as important. You want to think soup can rather than tuna can here; a tall and thin shape will maximize the convection created by the element, minimize the heat loss that prevents a good boil, and has the added benefit of reducing evaporation. Also, the bottom of the pot should be flat, not concave. Pots that have an aluminum core between layers of stainless steel will also give better performance by providing more uniform heat distribution.
If these limitations give you a moment of pause and you’re not willing to take the leap completely, that’s understandable. However, let me suggest that the only thing cooler than having a homebrewery . . . is having two homebreweries! Imagine it: a production system out in the shed, cranking out large batches of proven recipes for three seasons, and a smaller 2.5-gallon (9.4-L) pilot system for when the north winds start to blow, with you tinkering away in front of a roaring fire and perfecting the next season’s beers. For about $200, you can add an induction-powered secondary or pilot system to your brewing capabilities.
The Induction Brewing Process
Here I will detail a step-by-step guide to my brewing process, using two induction elements (primary at 1800W, secondary at 1300W — though you can easily use the single burner/pot and go to a no-sparge or extract method). “Temperatures” on the elements available in the US are usually measured in watts rather than degrees Fahrenheit, and are usually adjustable to 100 or 200W increments. (More advanced models have external temperature probes that can be placed in the pot. They will maintain your mixture at a precise temperature automatically, regardless of the liquid volume.) This process is for a 5-gallon (19 L) boil, 4.5 gallons (17-L) into the fermenter, with a cooler mash tun, a 1-gallon (3.7-L) mash out, and a batch sparge.
Pre-Heat Mash Tun
• 1 gallon (3.7 L) in primary at full power, boils in under four minutes.
• While heating, measure out mash water volume.
• Add to mash tun.
Mash Water
• Mash volume into primary at full power.
• Heats to strike temperatures 10-12 minutes (128 °F to about 162 °F/53 to 72 °C).
• Drain pre-heat water, and add mash volume and grain.
Mash
• Stir every 20 minutes.
• At 40 minutes into the mash, put 1 gallon (3.7 L) mash out over 1200W in primary, sparge volume into secondary over 600W.
Mash Out
• Add 1 gallon (3.7 L) of mash out water to cooler.
• Increase the temperature on the sparge water in secondary to 1300W.
• After 10 minutes, turn off the power to the secondary, vorlauf (pour the cloudy, husky wort back into the top of the lauter to clear the wort) and drain cooler into primary. Turn on primary element to 1200W.
Sparge
• Add sparge water, stir, and wait 10 minutes.
• Vorlauf and drain into primary, increasing temp to 1800W.
Boil
• Maintain heat at 1800W.
• Cover kettle to bring to a boil (usually about the time it takes to clean the mash tun).
• When boiling, remove lid.
• Boil for 60 minutes.
Post-Boil
• Turn off heat.
• Stir to create whirlpool, and allow sediment/protein cone to form (about eight minutes).
• Use wort chiller.
Finish Up
This process is not only efficient, it saves you time. Total active time using a direct-fire mash tun with a hot element is four hours. Using the same element but with a cooler-based mash tun saves you thirty minutes of inactive time, for a total of three hours and thirty minutes. The induction-based process, on the other hand, requires only two hours of active “brewing” time.
Final Word
This process works. I started using induction about four years ago, and in that time I’ve brewed nearly 100 beers across more than 30 sub-styles — ales and lagers, sour ales and IPAs, specialty, you name it. I just finished my second year on top of the leader board
for the Eastern Pennsylvania Homebrewer of the Year competition. Better than 90% of my induction-processed beers have won medals in competition (see my award-winning alt recipe on page 31), and those that didn’t failed in conception, not in process. There have been no concerns about precursors hanging around after a weak boil in any of my beers; no concerns about hop isomerization; no lack of melanoidin or caramelization in bocks or Scottish ales. Induction homebrewing is safe, cheap, and effective. It works, and you should try it!
Recipe:
Is It Cold In Here or Is It Just Me? Induction Alt
(4 gallons/15 L, extract with grains)OG = 1.054 FG = 1.013 IBU = 40 SRM = 21 ABV = 5.4%
This is my most reliably excellent beer. It’s won over a dozen medals, including honorable mention in the second round of the National Homebrew Competition (NHC), and ages beautifully. While most Brew Your Own recipes are 5 gallons (19 L), this is written as 4 gallons (15 L), based on my 5-gallon (19 L) induction brewpot — a good size for an 1800-watt element. This recipe can easily be scaled up, however, depending on your specific induction homebrew setup.
Ingredients
7.4 lbs. (3.4 kg) Maris Otter pale ale malt
0.75 lbs. (0.34 kg) Munich malt
0.25 lbs. (0.11 kg) Caramunich® I malt (37 °L)
0.25 lbs. (0.11 kg) Carafa® II malt (420 °L)
0.19 lbs. (86 g) pale chocolate malt (200 °L)
8 AAU Nugget hops (60 min.) (0.6 oz./17 g at 13% alpha acids)
1.2 AAU Hallertauer hops (5 min.) (0.25 oz./7 g at 4.8% alpha acids)
Wyeast 1007 (German Ale) or White Labs WLP036 (Dusseldorf Alt) yeast
Priming sugar (if bottling)
Step by Step
This is a single infusion mash. Mash the crushed grains at 150 °F (66 °C) and hold at this temperature for a total of 75 minutes. Sparge slowly with 168 °F (76 °C) water, collecting wort until the pre-boil kettle volume is around 5 gallons (19 L).
The total wort boil time is 90 minutes, with hop additions called for at 60 minutes and 5 minutes before the end of the boil.
Chill the wort to 60 °F (16 °C) and aerate thoroughly. Pitch the yeast and ferment at 60 °F (16 °C). After fermentation is complete, bottle or keg, carbonating to approximately 2.4 volumes.
Is It Cold In Here or Is It Just Me? Induction Alt
(4 gallons/15 L, extract with grains)
OG = 1.054 FG = 1.013 IBU = 40 SRM = 21 ABV = 5.4%
Ingredients
3.3 lbs. (1.5 kg) Maris Otter liquid malt extract
2 lbs. (0.91 kg) dried malt extract
0.25 lbs. (0.11 kg) Caramunich® I malt (37 °L)
0.25 lbs. (0.11 kg) Carafa® II malt (420 °L)
0.19 lbs. (86 g) pale chocolate malt (200 °L)
8 AAU Nugget hops (60 min.) (0.6 oz./17 g at 13% alpha acids)
1.2 AAU Hallertauer hops (5 min.) (0.25 oz./7 g at 4.8% alpha acids)
Wyeast 1007 (German Ale) or White Labs WLP036 (Dusseldorf Alt) yeast
Priming sugar (if bottling)
Step by Step
Steep your crushed grains in 2 qts. (1.9 L) water at 160 °F (71 °C) for 20 minutes. Rinse the grain bag with hot water, collecting the runoff. Top off your kettle to 5 gallons (19 L). stir in the extracts and bring to a boil.
The total wort boil time is 90 minutes, with hop additions called for at 60 minutes and 5 minutes before the end of the boil.
Chill the wort to 60 °F (16 °C) and aerate thoroughly. Pitch the yeast and ferment at 60 °F (16 °C). After fermentation is complete, bottle or keg, carbonating to approximately 2.4 volumes.
Written by Josh Weikert
Issue: March-April 2014
