Smoking malts at home is not limited to traditional styles, you can smoke grains over any kind of wood and pick up unique flavors from those woods. Nor do you have to limit the grains smoked to pilsner or wheat malt. Any grain can be smoked. By smoking different grains over differernt woods (either a single type or multiple types of wood) you can produce unique flavors that will make a smoked beer stand out as something unique, even in the smoked beer category. San Antonio brewery (and distillery) Ranger Creek makes a couple unique smoked beers. One is a Mesquite Smoked Porter with smoked maris otter. The other, easily their best beer, is Small Batch #2: a saison with spelt smoked over peach, apricot, plum and apple woods. It is complex with interested fruit and smoke flavor without bowling you over with smoke (a reason many people rate it poorly).
The issue home-smoked malt is often criticized for is the lack of predictable and repeatable results. Certainly one's home smoking process is likely less consistent than a professional maltster (or even a brewery) that smoked huge amounts of grain at a time. Still, like with brewing, if you understand your equipment and process you can reduce the margin of error considerably. Personally I don't mind a little variance in my beer so if one batch turns out a little more or less smoky than the next it's not the end of the world. However, the variance across batches of beer will also diminish by smoking enough grain to use in several batches so each has the same smoke profile. The process for smoking grain is easy and requires no more special equipment than what you would already use for smoking meats.
Home Smoking Grains Process
Some people prefer the electric smokers over the fire pit style smokers like this. You can use an electric smoker to smoke grains but you want a good thick smoke to smoke grains so make sure you can get enough wood smoking to create a thick fire. I don't think I've ever seen any electric smokers pour out smoke like a traditional smoker but then again I haven't seen that many in action.
If you are new to smoking I would recommend using the smoker a few times to learn how to control the temperature. Smoking meat is all about low and slow cooking with a very low temperature (for a fire). Similarly, when you smoke grains at home you are smoking grain that has already been kilned so it is dried out and already been hit with heat. If you smoke it under too hot of conditions you will continue to kiln the grains and develop a more toasted and darker flavor. It's not necessarily bad but you may not want your smoked beer to taste like toast and smoke. (Although bread that has been smoked and then toasted is tasty.)
Once you feel ready to smoke some grains you just want to follow the same process as starting your smoker for meats. My process is to start the fire with a mix of charcoal and dry wood to create a sustainable and low heat fire. I soak more wood in water for an hour or so and then add that wood to the fire. The water-smoked wood will smoke better and also will keep the heat lower. Your process may be different. Follow the process you are familiar with.
A note about wood choice: not all woods are safe or desirable for smoking. Some wood and other vegetative material contains chemicals that are toxic when consumed and those chemicals are released in a fire and end up in your smoked grains. The safest thing to do is to limit yourself to smoking woods you buy at the store that is sold specifically for smoking meats. Lumber and woods for other hobbies often contain preservatives that are toxic and the woods may be unsafe for smoking. If you are eyeballing trees on your property (or maybe you already cut up trees for firewood or smoking) still to the kinds of wood sold for smoking or at least do some research online in smoking/BBQ groups to make sure it is safe. Also, you will want to season the wood (meaning, age it in dry conditions for around a year or dry it in a kiln) because fresh wood can be very harsh and is generally not used for smoking meats for that reason.
You want your fire as low of a temperature as you can keep it while creating a healthy amount of smoke. Try to keep the temperature in the smoker at 120F or lower, if you can. Remember, you are not trying to kiln or cook the grains, just attach smoke. You will just want to keep lots of smoke and low temperature while you are smoking.
Preparing the grain for smoking is simple. Before smoking, you should soak the grain in a minimal amount of water. Like the wood, this will help keep the grain cool and the water helps the smoke stick to the grain. You really only need to soak it for thirty minutes or so. Some people soak for much longer but I find that is sufficient. The grain should be damp but not dripping water. It's not disastrous for the grain to be more than damp but you want the grain to dry out completely so it doesn't mold or stale after smoking and the more wet it is the more time it has to stay on the smoker. You can always add more water with a spray bottle but you cannot easily take it back out. I've never noticed a bad flavor from using too much water but if the grain gets too dry there will be more of a toasty flavor to it.
Then you want to spread the grain on whatever cooking surface you plan on using. Depending on your smoker, you may be able to use a cooking sheet like you would an oven. If you have a barrel-shaped smoker you probably need to use something else. A pie pan is a good alternative. If you don't have anything else, aluminum foil will work just fine. Create a shallow pan out of the foil by rolling up four sides of a sheet of foil and twisting the corners to create a wide and shallow box. You will need a more stable surface to transport the foil "pan" to the smoker and back off but it will work fine in the smoker.
The grain should be as spread out as possible. The deeper the layer of grain, the less the smoke will reach the grain on the bottom. You can mix the grain periodically to get even smoke but each time you open the smoker you vent out the smoke and change the temperature. It will also take more time to smoke all the grain so you're applying more heat to the grain, potentially toasting it more than necessary. An inch deep layer of grain is as much as I would recommend.
The length of time the grain will need to stay in the smoker will depend on several factors. The density of smoke in the smoker will affect how quickly the smoke penetrates the grain. The amount of grain and depth of the layer of grain will also affect how efficiently the smoke sticks to all the grain. The intensity of the smoke flavor from the wood will also make a difference. Some woods, like oak, have a milder smoke flavor and will take longer to reach the right intensity in the grain. Additionally, the amount of smoked character you desire in the grain will affect how long you leave it on the smoker. I like to smoke the grain to get a really intense flavor. It usually takes a couple hours to get a good smoke flavor and aroma in the grain although it may take longer depending on the above factors.
You can smoke other things while the grain is smoking although you should be mindful that temperatures as low as you want for smoking grains may be too low for most meats. However it is perfectly fine if you are smoking other foods, like vegetables. (Smoked jalapeno is delicious, even if you don't smoke them down to chipotles.) If you do have other foods, especially meats, on the smoker, make sure other food is not above the grains. Other foods dripping juices into your grain may cause off flavors. If meat is dripping into your grain it can not only carry off flavors and fat into your grain but since the meat is not at a safe temperature at that point you might get unwanted bacteria in the grains. Just another safety concern.
Once you're happy with the level of smoky character in the grain (and it's best to smell and taste it away from the smoker) just remove the grain from the smoker and let it cool. Some people insist it's necessary to put it in a bag and let it sit for a week. I don't find that necessary although the smoke character does mellow a little once the grain has cooled completely. You can let it sit for a few days or a week if you think it makes the grain taste better. Then use it in your beer as you prefer.
My random tips
- Assume that the diastatic power of any smoked base malt is now zero. Since you are adding additional heat to the grain, you are likely denaturing some of the enzymes used in conversion. If you can keep the heat extremely low you may not denature the enzymes but if you are smoking alongside meat in the upper 100s (or even in the low 200s) you definitely are denaturing enzymes. This means you probably cannot do a 100% home-smoked grain beer (unless you separately add enzymes, which you can) but you can still treat your smoked grain as a specialty malt.
- Choose the right kind of grains to smoke. It is very common to see base malts smoked, including pale malt/maris otter/2 row/6 row, pilsner, wheat malt and munich. It is not necessary to chose one of these malts although munich is a fantastic smoked grain. You can also smoke unmalted grains, such as unmalted wheat, unmalted barley, buckwheat, unmalted rye, etc. You can smoke them in either whole or flaked forms. Be careful about smoking specialty malts. Specialty malts are kilned to a particular temperature to produce a particular flavor profile. Adding more heat can change that flavor profile in a good or bad way. I would definitely avoid smoking any grain over 200 SRM to prevent adding additional kilning and making the grain too acrid. Sticking with base malts or unmalted grains is probably the best approach.
- Choose the wood or woods based upon the desired smoke flavor profile. Each wood has unique character and will impart completely different flavor in your beer. Fruit woods, for example, will produce some fruit flavors and a mild smoke. Oak smoke is slightly harsh but contains some citrus notes. I really enjoy mesquite flavor in both beer and food, so it is the wood I use the most. It has a delicious sweet, caramel flavor but it burns very hot so it's hard to keep a cool fire with it. Hickory also has a rich flavor but can easily overwhelm. You can mix woods to create a custom flavor profile. Hickory and beechwood would create a bacon-like flavor that might be more interesting than the straight beechwood rauch malt.
- An efficient way to smoke grain is to tack it on to the end of a day smoking meats. If you've used a smoker you know the smoker will stay warm for hours, even days, after you run out of food to put on it. Rather than trying to keep a low heat from a fresh fire, let the heat cool down after smoking meats and then put your grain on the smoker with a little fresh, water-soaked wood.
- Use the smoked grains in a reasonable amount of time. Smoke does not last forever, either on the grain or in the beer. The smoke flavor will fade, so keep the grains in your fridge if you can to extend their life if you aren't using them immediately. The flavor of well-faded smoke is not that pleasant so if you find some old smoked grains you probably want to toss them, although I have had some success re-smoking them. I would definitely use within six months if kept at room temperature and within a year if kept in the fridge.
- I would not use a grill as an alternative if you lack access to a smoker. Grills are meant to cook hot and fast so they would toast the grain faster than you could get a good smoke flavor. I guess depending on your grill you could start a very small fire with a lot of wood and keep it cool but that doesn't sound like it would work very well.