Kilning and flavour development

I came across this really interesting graph while looking for information on kilning and diastatic power. It’s from a presentation titled “Unraveling the Malt Puzzle” by Joseph Hertich and the Michigan Brewer’s Guild. It shows the importance of moisture content and kilning temperature on flavour development, specifically stating that the 145-155F 62C-68C range at 25-35% moisture content is the most optimal for flavour development. This is new to me, so far everything I’ve read about kilning pale malt states that the temperature shouldn’t be raised above 50C until the moisture content is below 10% I think I’ll give this a try.

 

Some new / old info on malting

Here’s some very useful information on malting from “A Textbook of Brewing” by Jean De Clerck published in english in 1958. These are not quotes, I’m just paraphrasing and adding my own thoughts:

On floor malting;

Firstly, the length of time malt spends germinating is much longer than I previously thought. The longer the germination the more enzymes develop. 10 -11 days in Great Britain to produce a fully modified malt for single infusion mashes. 7-8 days for the less modified malts on the continent.

Recommended germination temperatures 15-18 C for pale malts 20-25 C for dark malts.

Modification continues even when the roots start to wither. So no need to keep spraying water to keep the roots healthy looking. You actually want growth to slow down. The most active growth period is from day 3 to day 6. The build up of CO2 will also slow growth without inhibiting enzyme development, so a box with a lid is a good idea although I wouldn’t recommend plastic as it may encourage mould to develop.

The length of the acrospire is not a good way to judge the level of modification. Sometimes internal modification does not proceed as well as the growth of rootlets and acrospire. If this happens the temperature must be increased to 20-25 C even for pale malts. At higher temperatures roots can become tangled and matted together.

When highly modified malts are required eg. Munich malt, the rootlets are allowed to become matted which makes turning difficult and a plow type tool must be used to break it apart.

A better way to judge if the malt is modified is to observe the friability of the corn. To do this cut the barley corn along it’s length with a fingernail and rub between thumb and forfinger. If it spreads evenly and is relatively dry and chalky it is well modified. If not the contents of the corn roll into a ball between the fingers.

Happy malting!

 

Pale and Pilsner malts

 

 

Finally finished malting a batch of pale and pilsner malt. The only difference between the two is the final curing temperature. I made both with my 6-row Robust barely. Normally the other difference between pale and pilsner malt is that pale malt is made with 2-row barley which usually contains less proteins and has less diastatic power but contains more alpha amylase. My oven seems pretty maxed out at 5-6 lbs of grain which at this stage is at about 8 lbs due to the water it has absorbed. It all fits on four trays which I have to shuffle around during kilning so that it dries evenly. I’m no carpenter but the trays I made work and are fairly sturdy. I made them out of 1/4 inch plywood. I took an 18″x24″ piece and cut a 14″x20″ hole so that the sides are 2″ wide. I then stapled metal screen to it. The staples I used went right through the plywood so I had to bend the points down on the other side. I used a screwdriver and a mallet for this and pushed the points right into the wood. I then glued some 1″ pieces to go along the edge and cover the ends of the screen. I can’t wait to start brewing but I’m still planning on making some more base malts as well as acid, brown, amber, chocolate, and black.

Here’s the procedure I used to make my Pale and Pilsner malts which are the same until the last step.

Steep 8 hrs. rest 8 hrs and repeat until moisture content is 42-44% (usually takes 2-3 days) Pilsner malt 38-42%

Germinate until acrospire is 2/3 – 3/4 the length of the grain and the starch inside spreads like a chalky paste when rubbed between two fingers, as opposed to a gummy ball.

Kiln with ventillation at 95-100 F for 22 hrs

Raise temp. to 122 F for 12 hrs

Cure malt at 176F- 203F F for 2-3 hrs to create pale malt

Cure at 158 F-176F 2-3 hrs to create pilsner malt.

Shake off rootlets with a screen or seive