We thank all the attendees for actively participating in Scott Johnsn's webinar on "Fermentation 101" brought to you by CocoaTown as part of "Empowering Chocopreneurs" series. Scott was kind enough to curate the questions and answer them in detail. We have created a blog post with his answers as it will stay as a valuable resource for any cocoa farmer or Chocolatemaker who wants to understand and/or improve their fermentation practices. Big Thank you to Scott on behalf of all attendees and all readers who will benefit from this blog.
Answer: In general, a box should be a cube, and sized to hold anywhere between 300-600kg of wet beans. Anything in this range would be appropriate. Less than that, your bean mass may experience temperature variations overnight as it cools; more than that, and it’s difficult to work with.
Question: Is the shape cube? Or rectangular?
Answer: Cube will be optimal.
Question: Can you put the boxes side by side or 2 cubes with 1 side in touch with the other beans or there should be a minimum distance between boxes?
Answer: They can absolutely be side by side, sharing a wall. I’ve built multiple fermenteries in this very fashion, as it is an efficient use of wood and helps keep costs down.
Question: Can the cocoa butter extracted from unfermented cocoa beans can be used for the chocolate making process?
Answer: It can be, but for the reasons discussed, it is not advisable. Not only will your yield be poor, but the flavor also will be poor. If you choose to go this route, I’d advise that you sell the cocoa butter from unfermented beans (that you intend to use for chocolate production) to processors who will deodorize it.
Answer: The yeasts and bacteria responsible for fermentation are, quite literally, everywhere - they’re ubiquitous - meaning that as soon as you open your pod, nature has automatically added them for you. No need to add any additional organisms.
Question: Would the type of wood used in box fermentation affect flavor? Or can we use any wood for building fermentation boxes?
Question: Do you need to cover the box? Also, should we use banana leaves to wrap the box?
Answer: Great question - I should have included this topic. Covering the fermentation box is indeed advised, as it helps retain the heat generated during fermentation. Banana leaves are a fine way to cover the box, and simply place them on top of the fermenting cocoa. You’d remove them and set them aside when it’s time to turn the cocoa into a new box (aerating them), and then replace the leaves once the cocoa has been turned.
Question: How many days, do we have to keep the beans in the box for anaerobic and aerobic fermentation?
Answer: There’s no one right answer - your fermentation may range from 3-7 days (in general), and may have 1-5 turns). Each combination of days and turns will create a different type of cocoa bean flavor profile - so knowing what your customer is looking for is important in shaping how you ferment. Alternatively, you can present this flexibility to your customer, to let them know that you’re capable of creating multiple types of flavor profiles with the same beans - which increases your value to them!
Question: Is it necessary to measure the Brix degrees prior to fermentation?
Answer: It is not necessary - but it is advised. Doing so will help you know if the beans you are fermenting have enough sugars to achieve a proper fermentation. If the brix is less than 13 - you can expect that your fermentation will not work properly as there’s insufficient sugars to ‘feed’ the yeast.
Question: Does draining the beans in the bag overnight before putting in the fermentation boxes impact Brix measurement?
Answer: Yes, draining the beans overnight will reduce the brix from the liquid carrying sugars away - but remember, your fermentation has actually already started the moment you open your pod, even though you haven’t formally put them in the fermentation box yet (due to the yeasts literally being everywhere). As the beans are draining in the bag, they’re also simultaneously fermenting and reducing the brix.
Question: How long can we keep and open the pod and start the fermentation? There are instances that we have to wait for other harvests to accumulate the desired volume in the fermentation box.
Answer: What I’ve found is the best is to cut your pods off the trees during the day, and wait to open them until the evening when it’s cooler. We didn’t talk about fermentation kinetics (how fast or how slow a fermentation happens) - but the warmer the temperature, the faster a fermentation will progress (the yeasts “eat” the sugars faster). By waiting until evening to open the pods, the temperatures are cooler, which slows down the rate of fermentation until you can collect enough beans to transport them to the fermenters. Ideally - if you’re starting with mature beans with good brix levels, if you’re able to get them to the fermentary w/in 10 hours (or so), you should still have a very high-quality bean to ferment. I’m not an advocate of storing pods for long periods before opening. Doing so increases the likelihood of molding, disease/pest problems, and will increase germination rates.
Question: Do we have to keep the fermentation juice or dispose it off in the fermentation boxes?
Answer: Almost always, the fermentation juice simply is discarded. It runs off through the fermentation holes and goes into the earth. In some countries, it may be collected and used to make local beverages, however food safety can easily become a concern when doing this.
Question: Is a low Brix fermentation better?
Question: What is the optimum period from harvest to cutting the pods before fermentation?
Answer: Assuming you’ve harvested ripe, mature pods - I’d like to see the beans in fermentation within 24 hours of harvesting. Harvest pods during the morning and afternoon, and open pods in the evening, transporting beans to fermentation late at night. By morning, then, your beans should be in fermentation boxes and happily fermenting!
Question: How many times do you have to turn the cacao mass?
Answer: There’s no one right answer. Think of ’turning’ as a production tool you can use to create different types of beans, with different flavor profiles. A ‘common’ type of fermentation for a good chocolate character (with forestaro beans) might be a 7-day fermentation with 3 turns - one after one day, and then another at day 3 and day 5. To be clear - that’s not the only way to do it - you can use the same beans, with the same 7-day fermentation, and turn them every 2 days (so at days 2, 4, and 6), and still get very good beans - but they’d have a different flavor than the first scenario. It’s best to know what your customer is looking for, but oftentimes even they are not sure. What I’d advise in that case, then, is to do some experiments - where you create multiples types of fermented beans - and then convert them into either chocolate liquor or chocolate itself to assess the flavors of the beans. I can assist with that as well.
Question: Anaerobic is for 24 or 48 hrs.?
Answer: There’s some degree of all the fermentation types at all times however there are ’stages’ where one type is far more dominant. For anaerobic, those would be the yeast and lactic acid phases which are dominant for the first 3 days (more or less - it depends on how much turning you do in those first days. if you turn a lot during the first days, then the acetic phase (which is aerobic), will dominate earlier).
Question: When do I make the 1st turn, is it based on temperature achievement or time?
Answer: Time is the best way to standardize this - if you’ve controlled your raw materials (ie you know you have good quality beans, with high brix and not diseased or immature), and if you’ve standardized your fermentation weight (ie you always fill the box with, say, 400kg of wet, good quality beans), and it’s covered (so it’s not in direct sunlight or rain) - then your fermentation will be very, very predictable. I’d still advise taking temperature measurements, as that will warn you if your fermentation, for some reason, isn’t working right - so if you take your temperature and it’s too low - then the question becomes - what do you do to fix it? What I’d do in that instance (again, this assumes you have good quality, high brix beans to begin with) - then I’d switch my approach from one based on time, to one based on temperature - because at this point, you’ve got an unusual fermentation that you’re trying to fix. But again, if you’ve controlled your starting raw material, and you’ve standardized your process - this will rarely happen.
Question: What is the higher temperature in the acetic phase?
Answer: The more turning you do, the more oxygen you will introduce and the higher your temperatures will rise. It’s not uncommon for the temperature at the center of the fermentation mass to reach 48-50C.
Question: So other than making cocoa butter what other ways can we deal with the unfermented beans? Even though the yield is less but still going with cocoa butter which can be used for chocolate making is the best option, is this correct?
Answer: Unfermented beans have very little value, and it will always be more valuable as a fermented bean. That said, other than pressing them for butter - I can’t think of any other purpose for unfermented beans. They would not be accepted for use to make chocolate.
Question: Do you have an opinion on fermenting CCN51?
Answer: CCN51 can produce a very high-quality product. As with most raw materials, knowing how to treat it to get the most out of it is important, and the fermentation that is suitable for a non-CCN51 variety may not be the right fermentation to use on this particular variety. Oftentimes this is used as part of a cocoa bean blend, instead of being 100% of the bean source for a given chocolate.
Question: When you’ve emptied out the top-level box, can you fill it with the next batch of beans for fermentation?
Answer: I think this is in reference to the tiered box system, where beans are filled at the top box, and then turned by removing the front of the box and pushing them down into the next box. Doing so will result in the top box now being empty - so yes - that top box can be refilled. It’s important that it works with your fermentation method - see below two examples to illustrate:
- A three day fermentation, turning every day - refilling the top box would make sense, as each day the boxes below it are being turned - meaning that after day 1 when you’re ready to turn the top box - the box below it will be ready to be turned as well, ensuring that there’s an empty box for the contents of the top box to go into.
- A three-day fermentation, where turnings occur ONLY on day one - refilling the top box wouldn’t work in this scenario - as the second box won’t be empty (or turned) for another two days. At the end of day 1, when the top box is ready to be turned - there’ll be no where for it to go, as the box below it won’t be ready for turning yet.
Question: Can you already try doing a cut test without drying to check the fermentation?
Question: Have you experimented with adding yeast to the fermentation process?
Answer: Yes. My experience has been that it certainly doesn’t harm anything, but it also doesn’t provide meaningful benefit. I have seen some slight flavor differences, but in my opinion, it’s never been enough to justify the additional cost and logistical difficulties associated with doing this. Nature does a wonderful job of providing the necessary yeasts.
Question: Explain the impact of the following techniques on flavor development:
- 1) Pulp preconditioning – Pod storage prior to fermentation? - As noted above, I’m not an advocate of pod storage for the reasons noted, and generally speaking would advise against it.
- De-pulping – Washing off pulp - Washing off the pulp removes the ‘fuel’ for your yeasts, and as such a suitable fermentation will not be achieved. De-pulping the beans and attempting to ferment them would result in beans that have poor chocolate character, and would likely be quite bitter and astringent due the retention of the flavanols.
- Starter cultures – How do they work? - So, the thought process on starter cultures is that by providing a concentrated ‘dose’ of specific fermentation organisms - many of which are known to create distinct flavors in, say, the world of wine or beer (also fermentation processes) - that the fermenter can also direct their flavor profiles by choosing specific starter cultures. It does work to a small extent - but generally speaking, the impact is very small. I suspect that because cocoa fermentation is not occurring in a sterile environment (such as in a wine or beer brewery) - that nature is also contributing her own starter cultures, resulting in a mix of naturally provided yeasts and the yeasts in the starter culture - so you never achieve the full target state of a pure starter culture. Additionally, it obviously adds cost, and logistically it’s very difficult to keep live, active starter cultures viable in most cocoa environments.
Answer: Absolutely. Addressing various diseases and properly mitigating them takes on many forms, and the best way to deal with a pest/disease differs by the specific type of pest or disease.
Question: What about 2 days(anaerobic)-2days(aerobic) -1day-1day... Fermentation?
Answer: I’m not sure I understand the question - If the question is could you do a 4-day fermentation where for the first two days there are no turnings, and then the beans are turned daily for the next two days? Absolutely.
Question: Is there a way to turn the beans with limiting the contact with air in order to limit the acid but still have a longer fermentation?
Answer: Interesting question - This would be difficult to do, I’d think, without the creation of special fermentation equipment to do this. One of the main reasons for turning the beans is specially to introduce oxygen - so turning w/o aerating would eliminate the main reason for turning in the first place, but would, in theory, ensure a more homogeneous mix of beans. The first thought that comes to mind in how this might be done would be to incorporate an auger into the fermentation mass that ‘pushes’ beans up from the bottom of the box, which would allow gravity to ‘refill’ from the top of the box, but the weight of the beans might result in the auger simply crushing them. Give it a try, and see what you get. Send me some samples if you do it as I’d be curious
Question: During fermentation does it help to churn the beans in morning and evening on a daily basis?
Answer: What you’re proposing is, essentially, turning the beans every 12 hours. Doing so would increase the levels of acidity, and thus the sourness of the beans.
Question: When to make the 1st turn, is it based on temp achievement or time?
Answer: I find that the easiest way to manage this is based on time - again, if you’ve controlled your raw material (brix, disease free, etc.), and have standardized your fermentation (box size, drainage, mass) - then you’ll get pretty darn repeatable results, and you then use your in process quality measurements more as an indicator to help you know if the meshing is wrong and requires an intervention, as opposed to a process control measure that requires more active management. As long as your process is repeatable and consistent, it’s far easier to know that every day at noon you need to turn your beans, as opposed to waiting until a very specific temperature is reached, which is going to be far less predictable in terms of timing. Every process will have some inherent variation - and if you recall the chart i showed where I showed the average, high/low temps in a very specific fermentation - all of the product produced in that range of temperature was suitable - so it’s less about achieving an exact, precise temperature - and more about your fermentation being in the ‘acceptable range’ of temperatures. Now, if you want to be sure you don’t turn until you’ve reach a very specific, precise temperature - you can do that - it just requires a lot more management, and does raise the question of what are you going to do if your fermentation never quite reaches that temperature (what if it is 1 degree lower than you’d like)? How do you address that?