How the Pro's Malt

[AquaVitae]

The following was taken from a correspondence between a friend of mine and the gentlemen at a the local USDA Cereals Malt Lab. They talk about technical difference between rye, barley,corn and srghum. I figured it would be good to include this up here on the boards, enjoy:


Subject: Malting Protocol

I was referred to you by _____ I've been experimenting with a few procedures for malting my
own grains (corn, barley,rye) with some success, however I am told that
you are an expert in such matters and was wondering if you knew of a
malting protocol that consistently yeilds high quality malt (for beer
brewing) that could be performed at home using kitchen appliances and
utensils, I am already familiar with the basic regimen of alternately
steeping and air rest and then the drying but am looking to produce high
quality malts, any feedback you have would be greatly appreciated, thank
you for you time and have a nice day.


Sent Wednesday, May 5, 2010 3:23 pm

I deferred to my maltster for his advice on malting at home. We have a
malting protocol that will make a good base malt provided the barley is
a good malting barley in the first place. To get a consistently good
malt you need to start with good barley. There is a reason breweries
and malt houses have specifications that must be met. He has given
you a description of our malting protocol and some suggestions on how to
execute them in the kitchen. Are you intending to add the rye and corn
"malt" as adjunct to a barley malt brew or generate an all rye or all
corn "beer"? The enzymes present in barley are what make it so good for
beer. You will most likely have to add exogenous enzymes to an all rye
brew and certainly would have to do that for corn. You might have
gelatinization issues with corn as well. We have encountered that in
our experience with sorghum beers. Briggs book "Malts and Malting"
should give you a good idea on what will need to be done.

He works for me in our analytical lab and has made some very good
home brews though most have been all malt brews. If he has any
suggestions, I'll pass them on later.

Good Luck! And if you are ever short on beer tasting experts, we are a
willing group.

Cc:
Subject: RE: Malting Protocol


I would refer _____ to pp 722-736 of the excellent malting reference,
Malts and Malting, Briggs (ed), 1st edition (1998), Blackie Academic &
Professional Publishing, London.

Of the 3 grains mentioned, corn should be most difficult to malt because
it needs germination conditions which are warmer and wetter than for
barley and rye -- perhaps 25-30C. This means you'll need a vigorous
disinfection treatment before germination, or you may encounter fungal
proliferation problems. Sorghum, is analogous to maize, and I use 1%
bleach (hypochlorite) for 20 minutes prior to steeping, and 2 minutes
after steeping, with it. (Other disinfectants that are used include
dilute sodium or calcium hydroxide, borax/boric acid, and hydrogen
peroxide. So, remove obvious broken or infected kernels, sieve away
foreign debris, wash dust from the kernels, and then begin your steep.
(You could steep your corn kernels in a mesh sack inside a pot in your
sink, with 25-30C water constantly running over it; this would aerate
and change the steep water). For germination, you'll need something that
can maintain a high humidity to prevent dessication, and with sorghum, I
"water" the grain twice daily -- either spritz it, or soak it in water
for a few minutes. Like sorghum, due to it's single cell-layered
aleurone, Gibberellic Acid shouldn't enhance the production of modifying
enzymes, during germination in corn. With sorghum, most people use a
low kiln temperature of 45-50C for 24hours, to dry the grain, yet
preserve diastatic enzymes. In any event, most likely, these enzymes
will be much lower than for barley malt, and you'll need to add
exogenous enzymes.

Both with corn, and rye, you'll need to allow more space during
germination, and turn the grains more gently, than for barley, due to
their lack of a husk. Conversely, for this reason, you may be able to
use a shorter steep, as they should imbibe water more rapidly than
barley.

Barley is usually steeped at temperatures between 12-18C, with 12-16C
most typical. You need to steep barley until it's got a moisture
percentage of 45-46%, or it won't modify well, or to 42-44% for
under-modified malt. For large, plump barley, this might mean up to 48
hours, interpersing wet and air rest stages; small, thin barley might
require only 30-some hours of steeping. Though you should use humid
conditions for germination, and can spritz the grain with water, perhaps
daily, it's best to hydrate the grain well during the steep. You should
arrange to turn the germinating barley to prevent the growing rootlets
from entangling. People usually germinate barley in the 15-17C range
for 4-5 days. So, if you could set your refrigerator to this
temperature, a plastic ice cream pail with a ring of holes punched in
the side, and the lid on, might work well as a germination vessel. You
could turn the grain several times daily, and spritz the grain one or
more times daily, drain off excess water, and return the capped pail to
the refrigerator. A good kilning method may be your biggest hurdle for
home-malting barley. Generally, heated air is blown through the grain.
Low temperatures (less than 50C) are used until the grain moisture % has
fallen from the low 40%s to about 12%(About 10 hours by our schedule);
you must do this before raising the kiln temperature to preserve enzyme
levels in the finished malt. Then we ramp up to higher temperatures to
drive off bound water, and develop color and flavors: 4 hours (54C), 3
hours (60C), 2 hours (68C), and 3 hours (85C) -- the "curing" stage.
Could a food dehydrator function similar to this? Maybe you could lower
the moisture with a food dehydrator, and then use a convection oven to
add color and flavors to the malt?

You can use similar temperatures for rye, but Briggs says that it might
need 7 days of germination for full malt modification; also remember to
be more gentle with it than barley, because if the acrospire (shoot) is
damaged, germination ends.