Fail-proof “kotteri” (thick) authentic ramen soup that is so good

Kotteri ramen may be what made ramen the world-famous noodle cuisine

tonkotsu ramen

What made Japanese ramen the world-class famous cuisine, as popular as sushi may be its unique kotteri soup or thick/creamy soup that is often coupled with thin and hard noodles. They are often made of pork bones or chicken carcass by cooking them at high heat for long hours. They are called “Hakata Ramen” for the city name where this particular ramen type was originated or “Tonkotsu Ramen” for its main ingredients that are pork (ton) bones (kotsu). They are very popular because they are unique for the high-density stocks and low salinity levels and the low-hydration thin noodles. 

There are no similar noodle dishes in other noodle cuisines across the world. It is why several brands of Japanese ramen tonkotsu specialty shops have opened their shops in different countries and doing well for many years. But there is a challenge in doing this type of ramen. Making this type of broth is notoriously time-consuming, labor-intensive, and easy to make mistakes in making it good.

hakata tonkotsu ramen

Principles and methods to make superb kotteri ramen soup with consistency

Over the past 20 years, we have been teaching how to make ramen dishes from scratch. Everything from a variety of ramen soups and noodles each student wants to create, toppings, plating techniques to how to manage and operate ramen shops. Having taught over 2,100 students and cooked thousands of stockpots of kotteri ramen soups, we have fail-proof ways to make great and authentic ramen stocks.

Our students have been applying the principles and methods in operations of their successful ramen businesses. In this article, we will share the expertise and methods so that you can start applying the principles to make your own kotteri ramen soups with efficiency and consistency.

What makes great kotteri ramen great?


Before making kotteri ramen soup, we want to know what makes good kotteri ramen soup good. So, we are asking this question, what are the elements of great thick ramen soups? We think there are 3 points we should consider as the elements of great kotteri ramen soup. 

The first one is rich flavor with no unpleasant smell. As the thick ramen broth is often made by cooking animal-based ingredients, such as pork bones or chicken carcass, it is easy to get the unpleasant animal odors from these ingredients into the soup. The good thing is that we know where the odors come from. They are generated from blood and others that are present in the ingredients. To eliminate them from ramen stocks, we need to cook them in water at a high heat to bring out scums. As the remaining scums become the source of bad smells, we want to remove them thoroughly. 

The key is the cooking temperature and time. There is a certain temperature we can bring out the scums most efficiently. We want to keep the stockpot at the temperature for a certain length of time to remove all the scums from the ingredients. After that, we just need to cook it to a target density, which brings us to the next point.

High soup density with good umami concentration makes a good kotteri ramen soup

porkbone stock
stocks getting emulsified as the cooking intensifies over time

Kotteri partially means high in density, so it is no brainer that a good kotteri ramen soup needs to be high in soup density. But it also means a high viscosity. High-density ramen soup being viscous is another point that makes a good kotteri ramen soup as the viscosity helps the soup coat the noodles well. It helps improve the overall slurping experiences. To increase viscosity, we cook the ramen stock for long hours at a high heat.
Pork bones contain more collagen than chicken carcass, which release much gelatin and fat. But cooking them for long hours at a high heat eliminates floating oil and makes the stock cloudy. This phenomenon where a stock gets cloudy is called, emulsification where liquid stock and scattered oil get emulsified and dissolved into the stock.
Cloudy stock is well emulsified (having oil and stock blended well) with rounded stock tastes, showing another dimension of taste. Chicken carcass or whole chicken contain less collagen (protein) than pork bones, so we may add check feet, which contain lots of collagen for quicker emulsification.

High density/viscosity with good umami concentration makes a good ramen soup with a little bit of seasoning

motodare to base stocks
% of motodare added to base stocks across different ramen soups

A high-density ramen soup allows us to make good ramen soups with a small amount of seasoning, which is called “Motodare” in ramen soup. This may be a big reason many people across the world loves kotteri ramen soup. Japanese ramen soups are usually high in sodium, which many find too salty. This is because base stocks used in the soups are low in density and umami. So, a lot of motodare need to be added to them to taste strong enough to couple with cooked noodles. But when we have thick base stocks with a high concentration of umami, we only need to add a small amount of motodare to complete the soup, which is strong enough to be matched with cooked noodles.

People who are not used to salty ramen soup find tonkotsu soup or chicken paitan soup (cloudy ramen soup made mainly of chicken carcass) satisfying. As you can see in the comparison chart, the percentage of motodare added to base stocks is lower on tonkotsu ramen and chicken paitan ramen than other lighter ramen soups. (There are exceptions like tsukemen or dipping noodles because the dipped noodles need to carry flavors that are strong enough to sense.)

3 things that make kotteri ramen soup production commercially viable


So, we know the 3 elements of great kotteri ramen soups. And how can you make each of the elements so good that you craft kotteri ramen turns many into your raving fans? There are again 3 things you need to understand to make your kotteri ramen soup production commercially sound and stable. They are ingredients, methods, and equipment. Let’s discuss them each in detail.

variety of ingredients used for kotteri ramen soups, but you can also use a variety of vegetables and seafoods as well

Ingredients of course are critical in making great kotteri ramen soups. Reasons why bones, skins, trotters, feet, and all these parts that would otherwise be thrown away are used to make stocks were obvious, their low costs. Ramen shops make stocks from ingredients that are remaining of cut meats. They could make delicious ramen soups from the lost-cost ingredients. And what are the criteria for choosing good ingredients for great ramen stocks?
The first point is quality. But what are the high-quality ramen soup ingredients? One thing is how fresh they are. Bones that are freshly cut. And for chicken, we want to use chickens that stop laying eggs. Old chickens may not be good for the meat but great for soup making. Free-range chickens are better than broilers. That is the kind of quality we want for ingredients used in our ramen stocks.

We also want ingredients that are properly processed. There are certain things we wouldn’t want in ramen soups, such as nails of chicken feet or pork trotters. They should be properly removed before cooking them. Washing blood off pork bones or chickens help reduce the scums coming out in cooking. Preparing the ingredients before cooking them is very important in making high-quality kotteri ramen soups.

Soft water is a game-changer for your ramen soup production

soft water effect
water softer is relatively low priced and simple and easy to use. If your water is hard, we high recommend that you install it

Production equipment are also critical in making your kotteri soup production sound and commercially viable. Because production of kotteri ramen soup requires long hours of cooking, minimizing the production time is important. We should apply whatever we can do to reduce the time. 

The easiest and simplest equipment we can use is water softener. If the water you use is already soft enough, then you can skip reading this one, but if it is above 60mg/L (milligrams per liter), you should read on. Hard water contains a lot of minerals (calcium, magnesium, etc.), and they interfere with umami extraction when making ramen soups. After all, cooking base stock is just a process of moving umami molecules from ingredients into water or stocks.

When water these ingredients are cooked in has a lot of minerals in it, there is less room for the ingredients to be released to. So, it takes time to extract them into water. And some of the umami cannot be extracted and remain in the ingredients. So, it affects the production yield as well. Depending on the hardness of your water, use of hardwater affects the time and yield drastically. It may translate into tens of thousands of dollars in long run. (i.e.: longer hours of labor, less production yield, more utility costs – electricity and gas, etc.)

Strain your kotteri ramen soup with this soup strainer

hand-straining, especially kotteri (thick) ramen stocks can be very time-consuming and labor-intensive

Another equipment that should especially be used for production of your kotteri ramen soups is a soup strainer. After we are done with cooking of base stocks, we need to strain them, removing remaining of the ingredients (e.g., pieces of bones, meat fibers, etc.). Straining is usually done by hand. And this is a very labor-intensive and time-consuming work because hand-strainer gets clogged up with the remaining.

You would have to shake the strainer up and down and side to side to get the stock squeezed out. Depending on the density and volume of the stock, this may take hours. The stock is still hot, and we need to quickly cool it to secure the food safety. (i.e.: food danger zone 21 – 52 degrees Celsius or 70-125F) If this task takes hours, the stock may get spoiled (after hours of cooking).

So, we use a machine to strain base stocks. Our soup strainer, RichSoup uses the centrifuge system to strain hot stocks in a short period of time, automatically. (No shaking required) There is another benefit in straining ramen stocks by machine. Using centrifuge, all the stocks are squeezed out automatically. In hand-straining, some stocks remain in the remaining of the ingredients, which gets thrown away. We can hand-squeeze the remaining to see how much stocks remain there. This improves the production yield. 

Another good point this machine straining brings is the taste. In hand-straining, we tend to push the remaining of the ingredients in the strainer to squeeze stocks out of them. This also pushes small pieces of residuals into strained stocks. These ingredients pieces add coarse texture in our ramen soups like grains of sand. Some people don’t like it. But straining by machine, you can minimize these adulterants.


There are other equipment we recommend you use in production of your kotteri ramen soups. Heating capacity of stoves, sizes of stockpots, measuring devices, such as refractometers to measure soup density, etc., but please download the checklist of ramen equipment needed for a ramen shop business to find more about them.

Make the quality of your ramen soup high and consistent


The last thing is production methods we use. Over the past 2 decades, we developed production methods, called “Digital Cooking” where we digitize every variable of ramen production. So, anyone regardless of experiences can produce authentic, professional quality ramen over and over, just following recipes. We developed these methods when we encountered problems and overcame them.

They are based on science and empirical data we have accumulated over 20 years of cooking and conducting ramen courses. For example, we rely on the density of base stocks as an indicator of whether a particular ramen stock is done or not. Other variables we can control are salinity levels, sweetness, time, length, weight, size, temperature, ratio, percentage, speed, timing (time), etc.

By controlling each variable, we can reproduce the same quality over and over. This ability of reproduction creates consistency, which adds up to quality, which builds brand loyalty. Digital Cooking methods are strong tools you can use to start crafting your own kotteri ramen from scratch. And you can start learning them anytime anywhere at our Ramen School Online.

Production of Kotteri ramen soups can be labor-intensive, time-consuming, and difficult, but you can systemize it to relay anyone to run the production with consistent quality by applying Digital Cooking methods and using the right equipment and ingredients.

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Noodle Master: Akira Mii

Head of Yamato MFG International Dept., Ramen coach Thank you so much for your interest in Yamato Online Noodle School! My name is Akira. Over the past decade, I have been helping a great number of Ramen and Udon shops across the world. I am thrilled to use my experience and knowledge to help you along your journey of becoming a great Ramen master. Feel free to contact me!