Malting Gluten Free Grains

Why do we malt grain?

To create the enzymes that are needed during mashing to convert the starch to sugars.
To break down the cell walls in the grain, so that the enzymes will be able to get to the starch during the mash.
To break down proteins, into compounds needed for yeast growth, and head retention.
To break down gums in the grain so the sparge runs freely.
To develop colour (done during the kilning phase).
To develop taste (again during the kilning phase).

Now you can make a beer with unmalted grain, by using a number of different enzymes. These are the same enzymes found in malted grains, but are refined to a pure form and are added at stages in the mash, or even the fermenting wort. This process has been used to make gluten free beer. There are two commercially available examples world wide and I have tasted them both. I (and others) were not impressed, especially when you realise in one the colour is artificially added, so its not natural, but regardless, neither had any complexity to the taste, as you would expect in any beer.

These were made by companies that believe that you cannot malt buckwheat (one a multinational), or don't wish to spend the time and effort to do so. While this process certainly addresses the need to convert starch to sugars, it doesn't address the other attributes of malting, especially the complexity of flavours malting brings. This is fault of these commercial examples - no flavour complexity, and gives the wrong impression of gluten free brewing.

Malting Basics

You can malt any grain, the principle is the same regardless of the grain. Remember the seed is a food reserve for the germinating/growing plant, and if it could not break down the starches and proteins to simple compounds for food, it could not grow. The way the embryo plant does this is to make compounds called enzymes, and they can break down the food reserves into a form the plant can use. All we have to do is figure out how to highjack the seeds own processes to suit us.

The procedure for malting barley is easy to find out. The trouble is while the basic steps are the same for any grain seed, you cannot just use the barley seeds times and temperatures. They are suited specially to barley, other grains will vary, due to a host of conditions, such as : the size of the seed, the way it germinates, rate of water uptake, rate of enzyme synthesis, and percentage of compounds like oils, starches, proteins just to name a few.

The basic steps in malting are:

steeping - soaking the seeds in water. Generally we aim to get the moisture content of the grain up to 35-45%. The temperature is important, as you want to avoid overheating, generally 15C is ideal for barley. Also the grain needs good air circulation during this time. The purpose is two fold. To remove any build-up of heat, but more important the young growing plant needs oxygen to germinate and grow. Air is bubbled through the water, or air rests are incorporated in the steeping regime. This is simply allowing the water to drain away for a period of time, then replaced. During this time the roots should start to appear.
germination - Allow the drained grains to grow for a certain period of time. The grains must be kept moist, in the dark, and at a set temperature. Also the grain again must be have good air circulation, and should be turned regularly to avoid heat build-up, as well as separating the grains rootlets to stop them binding together.
drying - When the required amount of growth has occurred, the grains are dried. This is so the malt can be stored without spoilage and to protect and preserve the enzymes developed during germination. Fairly low temperatures are used in this stage so that the enzymes are not destroyed.
kilning - The dried malt is now kilned (roasted) to develop colour and taste, the temperature used will determine the colour and taste, and also what percentage of the enzymes are destroyed. Dark roasted malt will have all its enzymes destroyed.

Note that crystal malts are produced by a slightly different process, (basically stewing wet malt at mashing temperatures then drying) but it seems that crystal malts cannot be produced from gluten free grains. The problem is the gelatinisation temperature of the gluten free grains is too high. This means little starch is converted to sugar, thus we get little stewing of sugars that we normally get with crystal malt.

Malting Sorghum

Its sometimes hard for people from outside Africa to realise Africa has its own long history of beer making. Barley is not the native grain of Africa, sorghum and millet are. Sorghum and millet have been malted for thousands of years in Africa so that the Africans could make their own beers. The native African beers, have a low alcohol content, have lots of unconverted starch, and not only use standard yeast fermentation, but also use lactobacillus fermentation as well. The sorghum is also not roasted for additional flavour.

If one wished to make a European style beer, we need a sorghum malt which has a higher diastatic power than what they normally use (more enzymes), and we would like to kiln it to give it some colour and a more complex taste. We also want to minimise the malting losses (i.e. the amount of starch the seed uses to grow). The longer one malts the grain, that is allow the seed to grow, the more of the starch the embryo plant will eat. Its only natural. Allow the embryo plant to grow too long, and it can consume all the starch reserves. Its interesting to note, one of the characteristics we have bred into modern barley malts is a large grain with a large starch reserve, so that we have a good percentage of starch left over after the grain is malted.

The following method is one that I know works, as I use it with my home made malts:

Steeping - first wash the grain well to remove dust, broken grains and other rubbish (these will float naturally to the top and can be skimmed off). Then follow this steeping regime: 6 hours soak at 30°C followed by 3 hours dry; do this five times (45 hours), then a final steep of 6 hours at 40°C. Note that this takes a bit over 2 days, completely screwing up those two days for you, a good alarm clock and a willing partner are needed.
Germination - 4 days at 30°C, preferably in a very humid environment. Keep the grain moist by spraying with water. I recirculate the air to try and keep the moisture levels high, with low airflow.
Drying - 24 hours at 30°C, high airflow. Do not recirculate the air.
Kilning - So far all I have used is 4 hours at 40°C. This makes a good pale malt. I recirculate the air, it should have been dried in the last step. This is not very hot, but research suggests that any higher will start to wreck the enzymes (but they dry and kiln in one step). I suspect that by separating the drying and kilning, you might be able to kiln at a higher temperature, but I have not tried this yet.

The malt then needs to be cleaned, that is to remove the roots and acrospire (shoot). Two common methods are: shove the malt into a well sealed bag and place into your clothed dryer for at least 1/2 an hour (No heat of course), or, place small amounts in a sieve and rub off the roots and acrospire. Malt is generally not used for 2 weeks after malting, to allow it to mature.

Notes:

The varieties of sorghum I have used successfully are MR BUSTER (red) and LIBERTY (white). These are Australian varieties and may be known by other names overseas. On some American web-sites they warn about using red sorghum due to its high tannin levels. While this may be true in the USA, this is not true in Australia, we do not grow any high tannin sorghum in Australia.
Because of the temperatures involved, the initial washing of the grain is very important to try to minimise bacterial and fungal growth, The grain is steeped and germinated at temperatures that fungi and bacteria love. All grain will naturally carry bacteria and fungi on the surface, so washing helps reduce their levels.
The final 40°C steep is to retard root and acrospire growth, without killing the seeds. You will get a lot more growth if it is not done. If the growth is not retarded, the acrospire will end up being a lot more than 2-3 times the length of the seed. The loss of starch in the grain from malting sorghum is naturally very high (up to 30%), so we must employ any practice that reduces those losses.
Health Warning - Sorghum when germinating and growing makes a hydrogen cyanide precursor in the seedling and roots. During mashing (or digestion) highly toxic prussic acid (hydrogen cyanide) is produced. The level of this toxic compound likely to be produced varies widely depending on variety. This is why its important to clean your malt well. You should remove rootlets and any acrospire growth, as this is where this chemical resides. Note that this warning can be found on page 731 in ¨Malts and Malting¨ by D.E. Briggs. I have also seen personally warnings about not eating sprouted sorghum as the sprouts are poisonous.
We have had our sorghum beer tested for cyanide levels, and less than 1mg/litre was detected. This is well below the allowable level. Our sorghum malt is machine cleaned, which removes some but not all of the root and acrospire. This and fermentation reduces the level of prussic acid to safe levels.

Malting Buckwheat

Buckwheat is not related to wheat, and is not a true grain, in fact it's not even a type of grass. Common buckwheat is an upright plant, branched, up to 90 cm (36 in) high; the leaves are heart-shaped, the flowers white or yellow-white, and the seeds black and triangular. The seeds are used for livestock and poultry feed and are ground into flour. Buckwheat flour contains no gluten and somewhat less protein and somewhat more starch than wheat.

It has been used as an adjunct in beer, but never as a base malt to my knowledge. Because its not a grass, when it germinates you see two proto-leaves and not the single acrospire as with true grains. Buckwheat has a very strong taste, and on its own nearly everyone will report they don't like the taste. I have made a beer from just buckwheat malt and I found the buckwheat taste far too strong (reminiscent of Bi-Aglut beer). Although strong tasting on its own, I have found when you use it as an adjunct in brewing, up to 20-30% of the grain bill, it seems fine with no off taste. It also roasts nicely to provide colour and a nutty taste at these concentrations.

The following method is one I used once to make a malt with good enzymatic strength and can convert itself:

Steeping - first wash the grain well to remove dust, broken grains and other rubbish (this will naturally float to the top and can be skimmed off). Then follow this steeping regime: 6 hours soaking at 25°C followed by 3 hours drained. Do this three times, then a final steeping in water of 6 hours at 35°C.
Germination - 2 days at 25°C, preferably in a very humid environment. Keep the grain moist by spraying with water. I recirculate the air to try and keep the moisture levels high, with a low airflow.
Drying - 24 hours at 25°C, with a high airflow. Do not recirculate the air.
Kilning - So far all I have used is 4 hours at 40°C. I recirculate the air, as it should have been dried in the last step.

Notes:

The above procedure above has not been refined, and I am still experimenting, but it does produce a malt that will convert itself.
After the first steep with buckwheat, you will see an oily scum left behind, this is normal. Just rinse it away.

Malting Equipment

There are two essential pieces of equipment you will need, the first bit of gear is required for steeping (the grain is covered with water), and second piece is for germinating, drying and kilning.

Steeping Container

This is a relatively a simple piece of equipment. This is just an insulated container with a drain plug, (an esky is fine), plus you need a basket to hold the grain. The basket is needed as the drain plug will not completely drain the water, plus its easier and quicker to separate the grain from the water. You need an insulated container as constant steeping temperatures are essential for good results, and the temperatures need to be maintained within a few degrees, or you will get inconsistent malting results. Here are some photo's of my equipment below. On top of the box is a digital thermometer with a remote probe so I can monitor the temperature easily. But an ordinary glass alcohol/mercury thermometer will equally do.

The steeping box - 55 litre esky

Plastic basket lined with shadecloth

The soaking buckwheat

Germinating, Drying, and Kilning Box (Malting box)

This essential piece of equipment you must build. It is really just a tray with a perforated bottom, and a means of blowing controlled temperature air through the grain as it rests on the tray. An essential feature is to be able to either recirculate the air or just blow air through it. The air temperature must be controlled as air that is too hot will not only kill the young germinating seeds, but also destroy the enzymes in the grains.

My first attempt was to use a fan heater which had a thermostat, but the problem with it was it has only two heat settings; low and high. On the low heat setting, the air temperature coming out of the heater was far too hot, so hot in fact it destroys the enzymes in the grain. The solution was to modify the wiring on the fan heater to include a light dimmer in the circuit for one of the heating elements. (1,000 watt and 2,000 watt light dimmers are available from your friendly electrical supply store. and cost $150-$200). This allowed me to adjust the current to the heater, thus adjusting how hot it got. I also installed a two speed fan from a space heater in the lid of the box so I could control the airflow. To recirculate the air is as easy as using some flexible pipe to connect the exhaust of the lid to the inlet vent of the malting box.

There are flaws in my design, the worst being quite a bit of water will drip into the inlet of the malting box (when recirculating moist air), so be sure to have some sort of drip tray underneath. Also, make sure all of the wood has been sealed with a waterproof paint or varnish, especially on the inside of the box, as moist warm air will encourage fungal growth on any unsealed surfaces.

You should note that most modern fan heaters are held together with anti-tamper screws. designed specially to stop people like me modifying the fan setup. Unless you know what you are doing around electricity, I strongly urge you to use an electrician to make the modifications to the fan heater. Water and electricity are a very dangerous combination. When moist air is recirculated, water will condense on the inside of the recirculation pipe and drip into the inlet of the malting box. You don't want the electrical current shorting across this condensation, so be careful in your design, and be extra careful with any modification to the fan to avoid this danger.

I have attached some photo's and a circuit diagram for my setup below. The fan heater is directly under the controls, in an enclosed section on the bottom of the malting box, the fan heater naturally sits into the wall. The (heated) air goes into the bottom of the box, the inlet for the fan heater is the hole adjacent to the controls. To recirculate the air the plastic hose feeds the output from the top to the inlet at the bottom. To dry the malt, a hose takes the output air from the top and is directed to an open window.

I use two digital thermometers for better control of my temperatures, one to monitor the temperature of the air going to the grain (the "on air temp") and one to monitor the temperature of the air after it has passed through the grain (the "off air temp"). Unless I say otherwise, any temperature I give (germinating, drying or kilning) are the "on air temperatures." This is where you calibrate the system.

The complete malting box, recirculate air	The malting box controls	The top removed, germinating grain
Malt box top showing fan	Malt box tray (middle level)	Malt box bottom (showing fan heater)
Circuit diagram

Making specialty Malts

The malting methods I have described so far, will only produce very pale malts, which can be used for making very pale beers, such as pseudo pilsners and wits. To produce beer with some colour and different flavours, you will need to make some roasted malts.

An easy way is to follow the directions given in the "Home Grain Roasting" webpage on the Australian Craft Brewing website. I have tried this with these malts and the results are very good. You may have to adjust the times recommended on the site, as they are based on barley grains, but the roasting principle is sound, and can be used for these grains.

The thing to remember is that roasting will destroy all of the diastatic power of the malt. I have found that Buckwheat produces quite good roasted malts, but to avoid the strong Buckwheat taste, use it only up to 15-20% of the total grain bill.

Results and Discussion

The malts you make using this process will have a lower diastatic power than ordinary malting barley, and also has higher gelatinisation temperatures for its starch than barley. This means if you want to test your diastatic power of your malt, ie how well your malting went, the standard malt testing procedures that is used on barley just wont work. Equally when using this malt, as its not like barley, special techniques must be used in order to brew with this malt.

On a final note, the malting properties of sorghum will vary greatly depending on the variety used, as sorghum is mainly used for stock feed, and it's very common for different varieties to be mixed together once they leave the farm. So it can be difficult to buy a specific variety of sorghum. But not impossible. It does require some shopping around, but its worth getting the right variety, for in any kind of malting, be it barley or sorghum, you are after a consistent, repeatable results. One sure way to achieve this is to have the same variety every time you malt. It will certainly save you a lot of time in the long run, so is worth the effort to track down a single variety of grain. The best sorghum I have found for malting so far is MR BUSTER. The only buckwheat I have used so far is the organic sprouting buckwheat from Kyalla.

Table of malt properties.

Malt	yield	colour	description
Pale Sorghum	about 1.035	very pale	reasonable pale malt, will convert itself, low diastatic power, good as a base malt
Pale Buckwheat	about 1.029	extremely pale	will convert itself, but probably better used a basis for coloured malts
Biscuit Buckwheat	don't know	when used at 10%, give beer a light yellow colour	roasted at 150°C for 60 mins, I think its too light.
Amber Buckwheat	don't know	when used at 10%, gives beer almost a normal colour	roasted at 200°C for 45 mins, probably better at 60 mins.

Modified "standard mash" procedure for testing malt.

This is a modified and bastardised procedure for determining the Hot Water Extract for gluten free malts. It can also be used to determine the wort colour and the conversion time (starch to sugars). The one key factor you have to realise is these malts have a the higher high gelatinisation temperature than normal mash temperatures.

This test has also been adapted for home use, as I would expect that you (like me) will not have the expensive and accurate laboratory equipment normally required for such a test. The equipment you will need is: some sort of grinder to grind the malt finely (<0.2mm), scales accurate to at least 1 gram, thermometer (pref digital), coffee filter and filter papers, and a small SS pot with lid. Note that most measuring cups are not accurate, so to measure water volume the best method is to weight your water (1 ml = 1 gram at 20°C). So 360 ml is 360 grams of water.

Procedure

Finely grind more than 50 g malt (basically to a powder), then measure out 50g.
Add 360 ml of water at a temp not exceeding 48°C to ensure an initial mash temp of 45°C
Cover and maintain temp at 45°C for 30 mins, stirring at 10 min intervals.
After 30 minutes, cover and allow mash to settle for 30 mins to separate. A clear coloured liquid should form above a light coloured starchy grist.
Carefully pour off the clear coloured liquid into a separate pan, taking as little as the light coloured starchy material as possible, while still getting a reasonable amount of the liquid (say about 30%). This liquid contains the enzymes. Cover it and put it to one side, this can be allowed to cool, do not try to maintain its temperature.
Add 200ml of hot water to the grist, and bring it to the boil, stirring so that it does not burn. Watch the temperature carefully. When the temperature is >80°C, time it for 30 minutes and continue heating the grain to boiling. Totally remove it from the the heat after the 30 minutes time period. This step is to gelatinise the starch in the grains. You should see a darkening of the colour of the mash as the temperature gets to about 77-80°C, and it will thicken.
Cool to as least 65°C, and then add the liquid that was poured off earlier. Get the temperature to 63°C if necessary.
Maintain the temp at 63°C for two hours (saccharification mash), stirring every 10 mins (a warm oven set at about 60°C is ideal).
Determination of saccharification rate. One hour after getting a temp of 63°C, transfer a few drops of the clear liquid (ie just before stirring again) onto a clean cool saucer and add a drop of iodine solution to check if the conversion is complete (ie iodine remains yellow or slightly reddish). Repeat every 30 mins. I have found that conversion takes about 1.5 hours.
After 2 hours, cool the mash to about 20°C, and adjust its weight to 450 g using cool clean water.
Wait 30 mins, then pour the entire contents into your coffee filter (putting the filter paper first), return the first 50 ml to the filter and collect the filtrate for 1 hour.
Report the clarity of the wort as 'clear' or cloudy'. measure the specific gravity and colour of the final filtered wort. This should ideally be done 1 hour after collecting the sample, as the the enzymes could still be active.

Expression of Results

G = excess degrees of gravity of the filtrate taking water at 20°C as 1000 ie G = 100(SG -1) where SG is the specific gravity of the filtrate at 20°C.

Hot Water Extract expressed in l°/kg.

HWE 'as is' = (G * 8.773)/SG l°/kg

Hot Water Extract expressed as % soluble extract (%SE).

HWE 'as is' = (G * 2.278)/SG %SE