Custom Fermentation Lids, A Practical Salt Solution

There's a problem that everyone who ferments food on a regular basis runs into. What's a good way to limit the aerobic activity at the top of the make? Also, if it's a solid application like a miso (AKA amino paste), how do you keep it compacted when the carbon dioxide starts to build? There are many solutions, but none of them present a practical and inexpensive way that can be customized to just about any vessel. We think we're onto something that fills the void.

Custom Fermentation Lid (Side View)

A lid that is just smaller than the opening of the vessel while in contact with an amino paste is how miso barrels/vats are designed. The lid is sturdy enough to support weights/stones above to maintain the compression during fermentation. This allows as much contact area as possible with a gap that allows carbon dioxide to escape and liquid to overflow above the lid. However, the readily available vessels folks reach for are mason jars and they're not designed for this. The common solution for fermenting food in jars is to add an air lock to the cover so oxygen cannot get in and the carbon dioxide build up eventually limits aerobic activity. However, it doesn't address maintaining the compaction of an amino paste during fermentation. We addressed this limitation with a neat work around, but it's not adaptable any other vessel that one would choose to ferment in.

Custom Fermentation Lid (Bottom View)

So what are the common solutions for covering and weighting the top of an amino paste aside from a fermentation barrel and matching lid? It's pretty much weights for mason jars and crocks that don't quite cover the entire surface and require supplementing, most commonly with plastic wrap. There's always the option of using a bag of salted water, which can match the shape of a vessel. However, it's fairly limited by the density, tend to be difficult to keep in place and aren't friendly when it comes to adding weight above. These solutions are just workarounds for the custom lid and they're not great.

Compressed Table Salt is Denser than Water 

Let's get back to the idea of being able to practically and inexpensively form a custom lid. The lids used in miso fermentation barrels are cut to size. What if you could use just three things to accomplish the same thing on practically any vessel with much less effort?

All you need is a vacuum sealer, a vac bag roll width that is at least a couple inches larger than your vessel opening and table salt. As we all know, a box of salt is fairly heavy for its size. The density of salt is 2.16 g/cm3, which is more than twice the density of water at 1.00 g/cm3. We chose table salt because it's fine and can be compressed to eliminate as much air as possible. A quick water displacement test of the vacuum packed salt lid weighing 3.25 pounds puts us pretty much in the middle at 1.5 g/cm3. We found out quickly in our initial experiment that kosher salt does not compact as well and you pretty much end up with the same density as water, so it floats. The reason why we want the cover to be more dense than water, so it will sink if you're using it for an application to hold the solids below the brine.

Custom Vacuum Packed Salt Lid Set Up

Yes, we have considered using water plus table salt to fill the gaps help improve the density, but it's messier and is difficult with a home vacuum sealer. We didn't go with a sand, metal shot or ceramic powder as we were looking for a low cost solution that is accepted as food grade even though it doesn't come in contact. Those who have dealt with strict food safety inspectors will understand. If these are not limitations to you, feel free to explore these further. 

To make your lid, you first need to make the mold for the salt to fill. Measure three inches down from the top of the fermentation vessel and mark in a few locations with kitchen/masking tape. This assumes that you'll have two inches of salt and one inch of head space. Fill the vessel with any grains to the tape mark. Next, determine the length and width of the vacuum bag roll you'll need to cut. Position your vacuum sealer so the the opening is just above the vessel. The closer you get, the less bagging you'll need. Pull the bagging out until you are confident that you can fill salt on top of the grains that is 2" thick and be able to vacuum seal the bag. For really large vessels, you'll have make a two piece lid split at the middle.  Cut and seal one side to make the bag. You know what to do from here. In some cases, you may need to use the handle of a wooden spoon to get the salt to fill in the edges. There you have it. Your custom lid that took longer to set up than make and the toughest part was finding the books to get the vacuum sealer to the right level.  

As a side note, if you want to use this to weigh down ferments like kraut, kimchi, pickles or other applications you want to get solids below the brine. You just have to increase the gap between the cover and vessel opening. You can do this by cutting a long 2" wide strip of cardboard or whatever is flexible and gives you the gap you want and cutting it length so it can be placed in as a collar inside the vessel above the grains. This strip of material will make the salt lid smaller by the thickness. 

As background, we've done a little homework on what's out there for larger weights. The only ones we know of are the split doughnut shaped weights made for lacto-fermentation crocks. There are ceramic and glass versions. For a direct comparison, the custom salt weight we made in the circular vessel here is the size you'd use an off the shelf one gallon split doughnut weight for. Let's do a quick and dirty calculation. The ceramic weight is $20 and weighs 2.5 pounds. That puts us at $8.00/pound. Assuming you have access to a home vacuum sealer, which is reasonable these days, here's the breakdown. The cost of a standard 26 oz container of table salt is just under $1. Two containers coincidentally put us at the size we needed, so that's $2. On top of that, let's say the bag costs $0.50. The salt is $2.50 of materials and weighs 3.25 pounds. That puts the salt solution at $0.77/pound and that's ten times less. Also, as we mentioned before, it's not ideal for keeping all the solids below the brine and not the answer for containing a miso.

In closing, we're here because we ferment a lot and want everyone to have the flexibility of using any fermentation vessel. As part of that, we want proper containment, because it's less work to ensure good results. We think this is a pretty great solution. Yes, there are issues that come along with using a vacuum bagged salt. Concern about the plastic being punctured, then it's game over. Keep in mind that this is not easy to do. Vacuum bags are made to take a beating. Think about all the rough handling of the insane amounts of vacuum packed products that are frozen, piled up and transported everyday. Of course, there are things you can do to ensure it won't break. Bagging it a second time is the first thing that comes to mind. Putting a plate/tougher insulator to take the beating if you want to add weight on top.

If you have access to a commercial vacuum sealer and want to do this with standard square restaurant style containers. Use the shorter containers of the same size opening as the mold to make the salt lid. Follow through the sequence of pictures below.

Short Square Container to Form the Salt Lid Shape

Vacuum Packing in the Container in the Chamber

Vacuum Packed Salt Lid Fits the Deeper Container

We hope you're as excited about the potential of this idea as we are. We just came up with it and haven't had a chance to put it through its paces, so let us know your experiences. Do you have improvements and maybe even a better way?

As always, please share your discoveries so we an keep the ideas bouncing.

Hoshigaki & Umeboshi, Idea Icebreakers

When we started seeing green stone fruits this season, we couldn't help but umeboshi. In all honesty, we haven't made the real stuff and just followed guidelines as you can see in a past crabapple post. Well, you knew that and that's not why you're here. Let's go!

Gochujang Molasses Green Apricot Umeboshi

If you've ever made umeboshi before, you understand that the fruit needs to be salt packed and weighted. This is a fairly typical whole fruit/veg preservation technique for breaking down the cell structure to release juices and generate a brine to be reinfused. It also creates an interesting texture.

Vac Packed Green Plums, Lovage & Salt

We leveraged vacuum packing the fruit with salt and punchy flavors. The big advantage of containing the fruit this way is that it makes it easy to manage a single layer and weight them in small batches. Just alternate layers of the vac packed fruit with hotel/sheet pans then stick a weight on top.

So we waited and waited for the fruit to get squished. It was a few days and they were still solid and barely any liquid pressed out. Sometimes we don't mind waiting and sometimes we do.

Infusing Butternut Squash with Brown Sugar

Hmm... How does one break up plant based cell structure with very little effort. Ice crystals of course! We did leverage the freeze thaw technique with further trials of hoshigaki anything, why not umeboshi?

Post Freeze & Thaw Sugar Infused Squash

After an overnight stay in the freezer, we stuck the frozen vac packed sheets back into the stack of weighted hotel pans. The fruit compressed pretty much immediately after they defrosted.

Post Press Gochujang Molasses Infused Green Apricots

There it is. We've successfully bridged the gap between umeboshi and hoshigaki, two fruit preservation techniques that yield serious depth and flavor complexity. Honestly, the methods are similar enough that the cross pollination of products and flavors are infinite.

As always, please share your discoveries so we an keep the ideas bouncing.

Butternut Squash a la Hoshigaki

Every year there's a wave of folks preserving persimmons by making hoshigaki. As with all the investigations here, we wanted see where the core method would take us with what we had on hand.

We decided to try something outside the box. A tiny butternut squash happened to be in our Farmer Dave's CSA share. Why not?

The first step of hoshigaki is to peel the skin to make the fruit conducive to drying. That's easily done, but of course a butternut squash isn't quite the same as a persimmon. One big difference is the sugar content. The key to the preservation is the sugar concentrating as it dries. Based on a quick nutritional facts search, butternut squash only has a couple percent of sugar and persimmon clocks at 13%. Not even close. So how do we get there?

To bump up the sugar percentage, we vacuum packed molasses and turbinado sugar with the peeled squash for infusion.

After a few days in refrigerator, we took the squash out of vac bag. It was pretty wet. We decided to put the squash in the dehydrator to dry off the exterior prior to hanging. The other reason for doing this is to quickly create the skin that's typical of the beginning stages of hoshigaki. Also, there's no way we're getting it sun dried here in New England this time of year.

The overnight stay in the dehydrator at 135 F worked like a charm. We had a nice permeable and flexible skin that allows for massaging as the squash dries. Scary close to the beginning stages of hoshigaki.

The squash isn't quite done at this point, but it looks, smells and feels promising. The hard flesh in the neck section is breaking down, which was a concern. Very pleasantly surprised that it worked out. It's these unexpected successes that keep us all interested and creating. In case you didn't know, we're already onto experimenting with onion.

As always, please share your discoveries so we can keep the ideas bouncing.

Umeboshi Crabapple or Any Tart Fruit

Being open to flavors and textures that are off the beaten path leads to neat discoveries. This way of thinking not only brings you down the rabbit hole of discovering ingredients, but also has your flavor brain interchanging the drivers of any food making method.

When we went apple picking, there were crab apple trees interspersed to support pollination for the orchard. Of course, we couldn't help but try the fruit. Unfortunately, we went through several horrible astringent bites before we tasted something worthwhile.

The final tree was in an unexpected place on the border of the property that no one would normally approach. Honestly, the fruit from this tree was far better than anything we'd tasted on the farm that day. A blast of sweet tart that any engineered candy would be jealous of. Since our bag was full, we loaded up a tissue box.

Crab Apples Vac Packed with Salt and Tulsi

When we got them into the kitchen, there was some thought of what to do next. Then, a comment on a post from our friend Shawn suggested umeboshi. That's it!

Crab Apples Post 2 Week Salt Pack

Umeboshi is a Japanese salt preserved plum. It sounds simple, but the flavor has serious depth. If you've ever had one, it only makes sense to follow the preservation process with crab apples.

Crab Apples after Dehydration Day 1

Loosely following the method, the crab apples were vacuum packed with 10% salt by weight and a few healthy branches of tulsi, holy basil. We bought the lovely starter plant from our friend Jenny at Muddy River Herbals. After the fruit gave up its juices two weeks later, we put them in a dehydrator at 135 F because there aren't any sunny days around here for a while.

Crab Apple after 3 Days of Dehydration

After a few days dehydrating, the fruit became sticky, salty, tiny apple raisins. They were not nearly as salty as umeboshi, which made them pleasant to eat whole with a nice basil flavor coming through. We could have put them back into the brine they gave up as is traditionally done, but we didn't.

Crab Apples Vac Packed in Salt and Jasmine Tea

As with all that we do here, umeboshi is a powerful method that can be used on any tart fruit. Well, maybe just about anything you want to preserve can be done this way. We're thinking whole apples next.

As always, please share your discoveries so we can keep the ideas bouncing.

Arnold Palmer in the Rough - Foraged Tea & Lemonade

An Arnold Palmer is by far one of our favorite drinks. It's a perfect combination of equal parts lemonade and tea. The flavor play is a lovely harmony of sweet tart and astringent depth. With that understanding, we decided to take a chance by shooting through the woods to hit the green.

Smooth and Staghorn Sumac

Sumac is popping up everywhere around here and we're gathering enough to get us through the year. You'll often see the deep red formations of drupes popping out from the bushes along most Northeast highways in the summer. This tart fruit is used in Middle Eastern cuisine as a dried and ground spice.

Sassafras Leaves and Twigs

Sassafras is also prevalent in the woods of New England. During the summer, there's an abundance of new growth ready for the picking. The aromatics of the leaves and young twigs reminds us of Earl Grey tea. You may already know the dried & powdered form of the leaves as file, the thickening herb for gumbo. 

Smashing Sumac & Sugar

When it came to processing the sumac, we wanted to use it fresh. It's not easy to separate the berries from the clusters of stems. We cut away the central stalk with scissors, covered the clusters with sugar and started pounding away with the end of a French rolling pin. The sugar acted as an abrasive that helped separate and break down the drupes as they were smashed. After that, we submerged the berries in water and heated to a simmer to steep out the flavor and dissolve the sugar for a light syrup.

Fresh Sassafras Leaf and Twig Tea

Maintaining the freshness kick, we steeped torn leaves and broken up young twigs in hot water as you would tea. It had a wonderful aroma and tasted great. We had to use a lot to get enough flavor concentration. The kicker was the interesting viscosity due to its thickening powers.

Sumac & Sassafras Arnold Palmer

Once all the "hard work" was done, we strained out the solids, mixed the two, added ice to dilute and chill for a refreshing drink. It is one of the best Arnold Palmer spins we've done in a long time. We loved that the primary ingredients were foraged in our neighborhood. 

Strawberry Top Bronze Fennel Koji Kombucha

We hope this helps you think about lemonade and tea as concepts in order to unlock the potential of anything you love that fits. Also, you don't have to go far into the woods to forage for ingredients. Consider the flavor packed odds and ends that have been sitting for a while in your refrigerator, freezer, pantry and cabinets. Cooking is all about using everything available to you. Shed the preconceptions to make something truly inspiring.

As always, please share your discoveries so we can keep the ideas bouncing