Hi Kevin,
I'm not sure this will give you any better answers that you have received so far, but I saw your question and couldn't resist digging out a chicha paper I did for CBC about 25 years ago. It was a fun project!
Making Chicha
An Adventure with Andean Corn Beer
When a local librarian first called me about chicha, I had never heard of it. She had run across it in a book that was being planned for a community-wide reading and she was trying to tie together as many elements as she could. Chicha, as it turns out is a traditional, corn based beverage that is indigenous to South America, most particularly the Andean region. Its production has been documented back as far as the Chimu Empire of 900 – 1470 A.D. on the west coast of South America and continues today in both South and Central America.
In its early days, chicha occupied a position of importance, which crossed, and indeed bridged, social and economic boundaries. It played a vital role in the reciprocal nature of cross-caste relationships in early Andean society. Those in the upper levels of society were expected to provide food and chicha as part of the exchange for the labor provided by the lower levels of the society. Indeed, in yet another example of the failure of prohibition, an attempt by the Spanish to curtail the distribution of chicha in 1566 resulted in the crippling of production, as the Andean lords were unable to persuade the working class to render services without chicha being provided in return.
Chicha was most commonly produced on a large scale by groups of women referred to as Mamakuna or "Virgins of the Sun" but also, in other areas there were groups of men (chicheros) who produced chicha as a full time occupation and who maintained independence from any political control. Chicha was also produced by households on a smaller scale and that is largely how it remains today.
The principle ingredients in chicha are water and corn, often fortified with sugar and flavored with fruits or spices. The corn must be modified to make the starches more available for conversion into fermentable sugars and this is accomplished by one of two methods. The first may be the most traditional and is purported to make the highest quality chicha. This process involves grinding the corn to a fine grist and forming it into small balls, which are placed in one's mouth to be modified by the diastase present in saliva. These balls of moist corn meal are then flattened and placed in the sun to dry. A time consuming and tedious process to say the least. The product of this process is called muko. The second, and more common practice is to malt the corn in a manner very similar to malting barley in order to modify the starches for brewing. This product is called jora. What follows are the results my adventure in chicha production from the production of jora to the finished drink.
The Corn
The first consideration was how to modify the corn for brewing chicha. I had serious doubts that our customers were likely to be enticed into drinking the product of my spit or that I had the salivary stamina necessary to produce the roughly 9 pounds of muko that I was going to need to produce a small batch of chicha. So, jora was the choice. I chose to use blue corn because of the marvelous color that it gives to the finished chicha. The first step was to soak or steep the corn to increase its moisture content. I used cool filtered water and changed the water twice a day to avoid the development of undesirable micro cultures in the steep water.
After 48 hours of steeping, the corn was drained, rinsed and placed in a large plastic tub (24" x 36") to germinate. The tub was large enough that the corn could be spread about 1 1/2 to 2 inches deep which helped to keep it from heating up too much from the respiration during germination and also allowed good air contact. In order to prevent the germinating corn from drying out, it was kept loosely covered with damp towels. As in the steep, the corn had to be rinsed twice a day to keep undesirable mold or bacterial growth at bay. At first I was concerned that the water I was using for my rinse might be too cold, but I found literature on barley malting which indicated that the germination proceeded more evenly and produced higher quality malt at lower temperatures. So, I continued to use filtered water from my most convenient source, our cold liquor tank (≈ 40° F). When the malt was taken from steep to germination box, there were no signs of any growth. Within a day or a day and a half, rootlets began to appear and careful examination revealed the beginnings of acrospire development.
Growth of the acrospire is important because it provides a good eyeball estimate of the modification of the grain. In malted barley, it is generally considered that malt is well modified once the acrospire has grown from the base of the kernel to near the tip of the kernel. The only reference that I found indicated that the corn's acrospire should be allowed to grow to 2-3 times the length of the kernel, which seemed like an excessive level of growth to me. The more the acrospire and rootlets grow, the more starch they consume from the grain. During the first round of germination, I frequently cut open kernels from the base, or germ end, where growth originates to the opposite end. Starch that had been well modified appeared soft and white. Starch that had not yet been modified appeared to have a somewhat grayish hue and was harder and shinier. The slowest to modify was the starch at the end furthest from the germ and on the side opposite the acrospire. By the time the acrospire has surpassed the length of the grain by about 100%, i.e. it had grown the length of the grain and then that much again, the kernel appeared to be quite fully modified. I thought that this was the appropriate time to start drying the corn but I discovered that the corn continues to grow (and fairly rapidly too) during the early stages of the drying. It turned out to be better to begin the drying a little earlier when the acrospire had exceeded the length of the kernel by 50-75%.
I tried several methods for drying the corn. Sun drying, which would be more traditional is not a very good option in Kansas in February so I approached the problem with more mechanical solutions. I was targeting a maximum temperature starting at around 95-100°F when wet and working up to 115-120° F as the moisture level decreased in order to preserve the enzymes in the grain. Oven drying at the very lowest settings or using just the pilot kept a fairly steady, low temperature. The problem with the oven was a lack of air movement that resulted in a very slow dry. I considered using a couple of small, home scale food driers that were lying around but the racks tended to allow the corn to fall through and they just didn't hold very much. I ended up taking a rolling sheet pan rack, donated by a local bakery, and turning it into a custom drying box by sheathing the sides in Masonite and foam insulation and placing a rack of 6 rheostaticaly controlled100 watt light bulbs in the bottom. Ventilation came in the form of two large openings in the bottom and a pair of 2" diameter holes in the top. This proved to provide insufficient ventilation and the first batch molded overnight. The addition of an 85 cfm cooling fan solved the ventilation problem and the drier was ready for production.
The first part of the drying process involved removing as much excess moisture as possible from the exterior of the grain. This was accomplished by means of the kitchen's industrial salad spinner, which is large enough to hold the entire 10 lbs and spin-dry it. The spun corn was then spread on perforated sheet pans (18 x 26" – standard restaurant pans). 10 lbs of corn (dry weight) was spread evenly over 5 sheet pans and placed into the drier. An empty perforated sheet pan on the bottom level, just above the lights, served as a diffuser to spread the heat evenly and avoid hot spots on the lower pans of corn. As it turned out, the rheostat on the lights was completely unnecessary; they were perfect at full power. The combination of the fan and the lights kept the temperature rising steadily from around 90° F to 120 °F over the course of the 48-60 hours that it took to dry the grain. The pans were rotated twice a day to provide even exposure to the heat and air circulation. During the early stages of drying, the smell was a little scary. It smelled fairly sour and fermentative. As the corn dried the smell became sweet and wonderful (see sample). 10 pounds of grain yielded about 9 lbs of malt, representing a malting loss of 10%.
The Mash
Now it was time to brew. Nine pounds of malted corn was milled to a nearly flour like grist and mixed with Nine gallons of cool water. This thin corn soup was slowly heated to 160 °F and allowed to rest for 2 hours for conversion of starches into sugars. According to Bob Hansen from Briess Malting Co., different grain's starches have different gelatinization temperatures and at 144 - 162° F, corn's gelatinization temperature is much higher than barley's is at 124 – 140° F. At the upper end of the range, where the most complete gelatinization takes place, the amylitic enzymes are largely denatured making for a modest level of conversion. He suggested that either a decoction mash or the use of exogenous enzymes would be necessary to achieve full conversion. Since neither of those options appeared to fit in with traditional methods for brewing chicha and since chicha is not necessarily expected to be highly fermentable, I proceeded using a single temperature mash. At the end of 2 hours at 160° F a microscopic examination of the wort using an iodine stain indicated a partial conversion of the starches with previously dark blue and intact starch granules appearing as ruptured, pale purple disks under 400x magnification.
Traditional methods involved either allowing the mash to settle and removing the supernatant liquid or straining the mash through some kind of a basket sieve. I employed a method that adopted a little bit of both. A 1 1/2" x 16" stainless steel tube was loosely filled with rice hulls and fitted with hose barbs on each end. The liquid above the mash in the mash tun was drained through the rice hulls providing a little extra clarity. The result was 5 gallons of wort at 6° P with a pH of 5.6. This was boiled for one hour, during which time one pound of brewers crystals (sugar) was added to raise the gravity by 3° P. The final kettle yield was 4 gallons at 10.5° P and at pH 5.35.
The wort was cooled to 75° F and racked into a carboy to rest overnight, allowing for a possibility of formation of some lactic culture. Not being sufficiently patient to wait to see if a fully spontaneous fermentation would occur (nor feeling terribly confident that it would be a desirable thing), I pitched a small amount (≈15 ml) of English Ale yeast and allowed it to take hold and slowly ferment the wort. The first day saw very little activity, the second day saw a good layer of foam and by the third day there was a fairly active fermentation with about 2" of foam on top. By the fifth day, fermentation had slowed significantly and the chicha was deemed ready for trial. Samples were pulled and the chicha was found to have fermented to about 50% ADA.
The Chicha
Chicha is meant to be consumed fresh – indeed still finishing it's fermentation – so this seemed to be about ready. There was a marvelous corn aroma mixed with a distinct fruity nose that reminded me of strawberries. The still-active fermentation provided a nice tingle of CO2 and there was a slight tartness that may have indicated some success in achieving a slight lactic contamination. We filled growlers with the cloudy purple brew and, leaving them only loosely capped, sent them to the bar for sampling. The responses were varied but positive over-all. This being so far removed from what our customers think of as traditional beer, it was hardly surprising that they weren't lining up to get full pints. A couple of customers who have sampled chicha in South and Central America provided confirmation that we had achieved the basics of chicha although suggesting that next time I might try adding some spices or fruits as is common in chicha brewing today. True to what I'd heard, the one growler that I held back became thin and somewhat sour with a couple more days aging and lacked to refreshing character of the earlier drink. The extreme "best fresh" nature of the chichi and the difficulty of malting significant quantities of corn make it unlikely that we will ever attempt to brew it on a large scale but its curiously refreshing and unique flavors make it something to brew again for the folks who'll appreciate it.
------------------------------
Steve Bradt
Hopsteiner
Craft Sales Representative
------------------------------
Original Message:
Sent: 06-02-2022 10:45
From: Kevin Powers
Subject: Any experience with malted corn in the brewhouse?
Hi all, long time first time here.
We've been working on a project to use corn (maize) grown and malted somewhat locally (to ~2L). I've been doing some test work to see how to go about best practices for extraction (generally a 50/50 mix of base malt barley and then this malted corn, at various mash temps within the standard all-barley range). I've so far not had great luck. We've got a lot of limiting factors being a small brewery, so I'm trying my best to work with what we have here.
There seems to be some confusion in the articles/podcasts/ect I've stumbled upon about the need for gelatinization of malted corn. It's always been my understanding gelatinization isn't necessary for malt, since it's been "unpacked" during the malting process, but hydration and solubility are of course part of getting extract.
There's also some confusion with corn's gelatinization temperatures anyway -- textbooks list it in the ~149-163F range, however most of the practical applications of unmalted corn on the distilling side seem discuss bringing to 190F+ for an extended period of time. (In one small test I ran in-house I was not able to get any noticable additional extract from letting just the malt corn rest at ~170F for 20 minutes, before cooling and adding the malt barley back in enzyme range.)
Without going on too long, I'm wondering if anyone has any experience or thoughts on best practices to achieve a reasonable extract. Doing a long series of step ups is undesirable but possible, and doing cereal cooking is not something I'd like to spin up (and, on a related note, makes me wonder why I'm using malted corn instead of raw anyway, because I'm not in need of enzymes for our application).
Cheers!
------------------------------
Kevin Powers
Owner/Brewer
Powers Farm & Brewery
Midland VA
------------------------------