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Home Malt Production

When my brother Stephan and me started brewing beer we decided to make our own malt too. In a home brewers guide it said "Malt production is not feasible for home brewers". It was part of our motivation to prove this statement wrong. When we started out however, we didn't imagine the complexity of this task. The first trials in 1998 where quite disillusioning. After brewing half a dozen undrinkable beers we decided to first brew with commercial malt. Brewing with our own malt was postponed until we got the brewing itself right. This part here describes how we finally managed to produce good malt and a good beer from it. For more information on the brewing itself go to my Personal Beer Brewery Page.

We produced a lot of bad malt. In the process we learned a lot and optimized many things. I will not go into details of our missed attempts. Instead I want to summarize the measures that finally resulted in good malt. Just in case you want to try it ;-)

How is Malt being made?

Malt usually is made from barley, but sometimes also from wheat (wheat beers) or rye (creamy Ales). The barley grain contains starch, but we need sugar for the fermentation. The whole point of the malting process is to produce enzymes inside of the grain to later convert the starch into sugar. When making beer the yeast will then ferment that sugar into alcohol.

Luckily nature helps us here: the barley grain produces these enzymes by itself when it starts to grow into a plant. So we make the grain think it's time to grow by watering it. And we let it grow just long enough to get enough of these enzymes. Then we dry it to stop it from growing and roast it to get a good malty taste. Sounds simple? It is, but there's a few catches!

Use the right Barley

Reading home brewers literature can be confusing, because everything is considered very important. Only the right water, the right hop, the right yeast, it's almost like religion. After trying out many different ingredients I must say, it doesn't really matter. Depending on what ingredients you take the outcome may taste somewhat different, but it's good beer anyway. But not with barley! The standard barley we get here in Switzerland is used for cattle feeding and thous contains a lot of protein for helping the cattle grow. And that protein is the problem, the soup is hard to separate from the mash, the beer has a slimy deposit and foames over quickly and has a strange taste. Special brewing barley is a prestine species and contains only very little protein. So we made the additional effort and bought brewing barley at a farmer in southern Germany.

Germination

In order to make the barley germinate it must be put into water for several hours, then set rest for about a day. During that day it must be turned over regularly, otherwise it gets too hot inside of the heap, the germ buds stick together and the whole thing starts to rot. The watering and resting phase must be repeated for about five to seven days. When the germ buds reach about the length of the grain itself it is called "Green Malt". It smells like fresh cucumber. Now comes the kiln drying to stop the germination and get the malty taste.

What is important here is that the watering and turning over is done regularly. Especially the turning over should be done at least once every couple of hours. When the whole pile sticks together, smells funny or when the length of the germ buds varies too much, lower the temperature and turn over more regularly next time.

Stephan solved those problems by building a machine, the "Germinator" ;-) It consisted of a large plastic box. On the inside there was a cylinder, rotatable around the horizontal axis by a electric motor, similar to the drum of a washing machine. Two electric valves permitted to fill the box with fresh water and to empty it again. The whole thing was controlled by a small PIC micro controller board. The program was to flood the box for 2 hours, empty it again and turn the drum for 30 seconds every 5 minutes. The whole program was repeated every day. One had to add about 3kg of barley, turn on the machine and wait for five to seven days. The results where excellent, no compact blocks anymore, homogeneously germinated grains, no bad odors. Perfect.

The barley is filled into the revolving drum. That drum is mounted into the malting machine. The lower left image shows the maching filling up with water, the revolving mechanic and the one electric valve on the faucet. The filling stops when a certain level is reached. The little box controls the two valves and the revolving drum.

Kiln Drying

The drying itself is well documented in the literature, but normally for much larger amounts of green malt. Several things are important for "home malting".

The ovens found in regular kitchen are much too inacurate, especially at the lower temperature levels needed for malting. Our oven had temperature discrepancies of over 15 degrees! We took an old oven, mounted a down - throttled vacuum cleaner fan and a temperature sensor in the back and wrote a small Visual Basic Application to control the temperature through pulse width modulation of the heating elements of the oven. The application could now follow the desired temperature profile, which made it autonomous for the whole 20 hours process.

Due to the small amount of green malt it dries of much quicker than it would in a large kiln drying machine. But the malt shouldn't dry too quickly, so we had to control the amount of fresh air to keep the humitidy inside long enough. Therefore we installed a small fan that blew fresh air into the oven when needed. This fan was computer controlled also.

With the temperature profile we controlled the type of malt produced. Especially the last few hours at the higher temperatures made a difference here. Drying off at 80 degrees yielded good, standard malt while 100 - 110 degrees produced darker malt with more taste, but also more bitterness and probably not as much enzymes anymore. We also tried color malt and caramel malt, but not with much success.

The green malt (notice the germs) is put into the oven for drying and roasting. The oven has a vacuum cleaner motor for circulating air (center) and a small fan (left side) for fresh air.

Results

We had contact with quite a few home brewers. Most of them looked at us with disbilief when they heard we were making malt. One of them, Roland Michl, was a brewer at a micro brewery in the area. He offered us to make a chemical analysis of one of our malt samples. The result confirmed the quality of the malt and cheered us up quite a bit as he wrote back: "Your malt turned out very well. Really good job!".

Here the results from Roland:

Extrakt: 81,9% sehr gut (very good)
Friabilimeter: 75,0% befriedigend (ok)
Ganzglasige: 1,6% gut (good)
Würzefarbe: 4,3 EBC zu dunkel (too dark)
Kochfarbe: 6,8 EBC zu dunkel (too dark)
Würze pH: 5,85 5,6-5,9
Eiweiss: 8,7% <10%
Feuchte: 4,2% <5%
VZ 45: 35% 36-39%

Further, Roland wrote (in german):

Fazit: Das Malz ist sehr gut geworden. Wenn man es mit handelsüblichen Pilsener Malz vergleicht, so fällt folgendes auf:

Keimarbeit ist sehr gut (hohe Löslichkeit, gute Mürbigkeit).

Eiweiss ist niedrig (liegt an der Gerste).

Die höhere Farbe, Feuchte und pH bzw. leicht niedrigere VZ 45 und Mürbigkeit liegen m.E. an einer etwas zu schnellen Schwelke und erhöhten Abdarrtemperatur. Aber da Ihr ja in einer sehr dünnen Schicht darrt, ist das auch im Bereich eines sehr guten Malzes. Ihr solltet evt. euer Maischprogramm den niedrigenen Enzymaktivitäten (VZ 45) anpassen und erweiterte Eiweiss- und Maltoserasten fahren. Wenn das Bier geschmacklich nicht an das aus Handelsmalz herankommt, so kann das evt an einer nicht vollständigen Verzuckerung liegen. Also immer die Jodprobe machen (auc bei Pfannevoll- und Ausschlagwürze).

Ihr könnt jederzeit nochmal Malz zur Analyse schicken. Wirklich gute Arbeit!

MfG Roland.

Conclusions

Malt production is doable for home brewers, but it is a lot of work, much more than brewing itself.

Not everyting home brewers say was important really is. But some things are. How do you find out which ones? Well, try it out. Our finding was that it is important to use the correct type of barley :-)

Malt production is only reasonable when automating. Letting the barley germinate and dry is so care intensive you almost need a 24h shift operation without automating it.

What happend here? The revolving mechanic in our "Germinator" broke so the barley wasn't turned over anymore. Classical "Overgermination" :-)