Background
Amazake (甘酒) is a traditional japanese beverage typically made from rice and rice koji. Rice is cooked, cooled, and then mixed with equal parts of koji, by weight, and water. The koji enzymatically breaks down the carbohydrates – i.e. the starches in the rice – into sugars. The result is a sweet, non-alcoholic liquid that has no exogenous forms of sugar. The amazake can then be modified – strained, clarified, blended, etc… – and added as the base of an ice cream, incorporated into a dressing, cooked down into caramel, or used to make a vinegar.
We’re exploring a few possibilities with amazake
- What substrates, other than rice, rice koji, and water can we use?
- What waste products can be upcycled through amazake?
- Can amazake be used in secondary or tertiary fermentations?
- What larder items can be developed with amazake?
Why does amazake, and amazake-variants, excite us?
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Amazake is a natural sweetening agent. In the United States, we rely heavily on refined cane sugar (or beet sugar), a pure white and heavily processed form of mostly sucrose. The sugarcane is mostly grown in the southern US, trucked to various east coast refineries, and then shipped again globally. Amazake has a more diverse nutrient profile with several types of B vitamins, is easier to digest & has low glycemic index (which minimizes blood sugar spikes).
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Amazake can be made with most starchy ingredients. Grains, which are critical to small-medium sized regenerative farms in the Northeast, like Rye, Spelt and Einkorn are excellent candidates for Amazake. Early tests suggest that Amazake-ing these grains can develop more complex and compelling flavor profiles, like citrus and caramel. Other starchy ingredients, from potatoes to beets, can also be used. Amazake offers the possibility of naturally developing, through koji-fermentation, sweet food-stuffs from ingredients that grow abundantly here.
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Amazake can be incredibly delicious and interesting. Blend strained amazake with poached rhubarb and you have a delicious drink that is akin to a drinkable yogurt. Toast rye berries, combine with rye koji, fermented, and then reduce down, and the outcome is a warm and dulce de leche like caramel that is made from just a single grain – no dairy, no sugar.
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Amazake is relatively easy to make and replicate at home. Amazake is typically made from just two ingredients – rice and koji – and requires no special equipment. In most of our amazake experiments, we use a dehydrator set to 135°F-140°F to produce in Amazake in 12 to 16 hours. Without a dehydrator, an amazake can still be made at room temperature over several days.
Background
The goal of this experiment is to run four parallel Amazake tests using different koji substrates and equipment setups to evaluate sweetness, sourness, and overall enzymatic activity.
The standard trials were conducted in the Alto-Shaam, with an additional duplicate rice trial run in a dehydrator to compare temperature consistency and heating rates.
Process
Four distinct batches were prepared using a 1:1:2 ratio (1 part koji, 1 part water, 2 parts secondary substrate):
- Wheat Koji: Prepared with Wheat koji.
- Oat Koji: Prepared with Oat koji.
- Sorghum Koji: Prepared with Sorghum koji.
- Rice Koji: Prepared with Rice koji and a secondary substrate.
Equipment
- Alto-Shaam
- Dehydrator (used for the duplicate rice koji batch)
Notes and Observations
Tasting Notes by Batch
- Sorghum Koji (Alto-Shaam): Came out extremely sour.
- Wheat Koji (Alto-Shaam): Not very sweet; exhibited slightly sour and bitter notes.
- Oat Koji (Alto-Shaam): Extremely sour.
- Rice Koji (Alto-Shaam): Sweeter than the other grain trials, but still carried a distinct sourness.
- Rice Koji (Dehydrator): This trial yielded the sweetest result. While still not quite as sweet as desired, it was noticeably superior to the Alto-Shaam batch.
Equipment and Temperature Analysis
The dehydrator performed significantly better than the Alto-Shaam for Amazake production. There are two primary hypotheses for why the dehydrator prevents the souring associated with lactic acid bacteria (LAB) activity:
- Heating Rate: The Alto-Shaam may take too long to bring the substrate up to temperature, allowing a window of lactic activity to occur before the heat kills off or inhibits the bacteria.
- Temperature Consistency: The dehydrator may hold a consistent 140°F (60°C) more reliably than the Alto-Shaam.
If using the Alto-Shaam in future trials, it may need to be set higher (perhaps 150°F–160°F / 65°C–71°C) to compensate, or the substrate must be pre-heated.
Ratio and Enzyme Observations
- When using fresh koji, a higher proportion of koji to secondary substrate might be necessary to ensure optimal enzymatic activity.
- Interestingly, increasing the substrate relative to the koji in the dehydrator trial still yielded roughly the same level of sweetness, suggesting the substrate ratio can be pushed higher under optimal temperature conditions.
Future Adjustments
- Reduce Incubation Time: Shorten the incubation window. Current trials ran for 14–16 hours; the next trials should be tested at 8 hours.
- Pre-heat Substrates: Pre-heat the secondary substrate and water before mixing with the koji to rapidly pass through the danger zone for lactobacillic activity.
- Alto-Shaam Calibration: Run a test in the Alto-Shaam at 150°F–160°F (65°C–71°C) to see if it prevents souring.
- Koji Ratios: Experiment with higher koji-to-substrate ratios when working with fresh koji to maximize amylase activity.