Buying guide
Advanced Fermenter Upgrades
Updated How we research
Once the basics feel routine, these projects open a new tier of fermentation. A tempeh incubator and koji spores unlock homemade miso, shoyu, and amazake, while natto supplies cover the boldest soybean ferment of all. On the drinks side, jun tea, water kefir, and a real ginger beer plant give your brewing rotation three fast, lively new cultures. The page is split into six sections (Tempeh Incubators; Koji Starter Spores; Natto Making Supplies; Jun Tea Supplies; Water Kefir Kits; Ginger Beer Plants), followed by every pick ranked by our score so you can compare them in one place.
The short version
We compared 24 picks. Our scores range from 6.1 to 8.6 out of 10.
- Best overall:FermentPro 12.8L Smart Fermentation Machine for Yogurt, Natto, Tempeh and Sourdough. Highest overall score in this guide at 8.6/10.
- Also great value:Kawashimaya Natto Starter Powder 3g (0.1oz), To Make 10-30kg of Homemade Natto, Bacillus Subtilis From Soybean Extract. Value score of 9/10, overall 8.6/10.
- Solid build:Kawachi Yellow Koji Starter Spores, 0.53oz (15g) Tane-koji oryzae Mold Spore Starter for Japanese Fermented Foods, Miso Soy Sauce. Build and materials score of 9/10, overall 8.6/10.
- Feature-rich:GRANURA HOME Bread Proofing Box, Sourdough Starter Warmer & Dough Proofer. Features score of 9/10, overall 8.1/10.
Scores are our editorial assessment, not customer ratings. How we score
Tempeh Incubators
- FermentPro 12.8L Smart Fermentation Machine for Yogurt, Natto, Tempeh and SourdoughOur score8.6/10
- GRANURA HOME Bread Proofing Box, Sourdough Starter Warmer & Dough ProoferOur score8.1/10
- UMJIGF 3.5L Natto Fermenter, Electric Natto Maker with Smart Panel ControlOur score7.3/10
- Automatic Electric Natto Fermenter Maker 3.5L Stainless Steel for Yogurt and TempehOur score7.0/10
Koji Starter Spores
- Kawachi Yellow Koji Starter Spores, 0.53oz (15g) Tane-koji oryzae Mold Spore Starter for Japanese Fermented Foods, Miso Soy SauceOur score8.6/10
- Hishiroku Kairyou Chohaku-kin Koji Starter Spores 0.7 oz (20g) SachetOur score8.4/10
- Shirayuri Koji (Aspergillus oryzae) Spores Gluten-Free Vegan - 200g/8ozOur score8.0/10
- Shiragiku Koji (Aspergillus oryzae) Spores Gluten-Free Vegan - 10g/0.35ozOur score7.6/10
Natto Making Supplies
- Kawashimaya Natto Starter Powder 3g (0.1oz), To Make 10-30kg of Homemade Natto, Bacillus Subtilis From Soybean ExtractOur score8.6/10
- Kawashimaya Natto Starter Spores Powder, Made From Soybean Extract (30g)Our score8.1/10
- Japanese Natto Starter Spores (Nattomoto) - 3g, 100% Organic Soybean Extract, Product of JapanOur score7.8/10
- Cultures For Health Natto Starter Spores, Traditional Soybean Japanese Food, Gluten Free VeganOur score7.6/10
Jun Tea Supplies
- Fermentaholics Jun Kombucha Starter Culture - USDA Certified Organic Jun SCOBY and Starter Tea, Makes 1 GallonOur score8.4/10
- Fermentaholics Jun Kombucha Essentials Kit - ORGANIC JUN SCOBY (starter culture) + 1-Gallon Glass Fermenting Jar, Breathable Cover, Rubber Band, & Adhesive Thermometer - Brew jun kombucha at HomeOur score7.6/10
- Fermentaholics The Complete Jun Kombucha Brewing Starter Kit, Organic - Make Jun Kombucha at homeOur score7.6/10
- Jun Scoby with Starter TeaOur score6.1/10
Water Kefir Kits
- Water Kefir Essentials Kit - ORGANIC WATER KEFIR GRAINS (starter culture) + 1-Quart Glass Fermenting Jar with Breathable Cover + Rubber Band + Adhesive Thermometer - Brew Water Kefir at HomeOur score8.2/10
- Natural Probio Water Kefir Grains - Starter Culture Kit with Complete Guide, Recipes and TipsOur score7.6/10
- LIVE and ACTIVE Florida Sun Kefir Water Kefir Grains TIBICOS DIY ProbioticsOur score7.3/10
- LynxLink Kefir Starter Kit - 64oz Thickened Glass Kefir Jar with Lid - Metal-Free Fine Mesh Strainer for Milk & Water Kefir - Complete Fermentation Kit with Stick-on ThermometerOur score7.0/10
Ginger Beer Plants
- Yemoos Dried Authentic Ginger Beer PlantOur score7.9/10
- Ginger Bug Probiotic Soda Starter - Live Dried Cultures with Root Beer and Ginger Beer RecipesOur score7.2/10
- Ginger Beer Plant Kit - Make Your Own Ginger Beer at HomeOur score6.7/10
- Authentic Ginger Beer Plant CultureOur score6.7/10
All 24 picks, ranked by our score
Every product from the sections above, listed once. Sort by the criterion you care about most, or tick up to three to compare.
#1FermentPro's 12.8L smart fermentation machine for yogurt, natto, tempeh and sourdough projects.
Fit for the job 9/10 · Features and specs 9/10 · Build and materials 8/10 · Value 8/10
- + 12.8L chamber fits trays of tempeh or several yogurt jars at once
- + Smart controls handle the warm, steady heat tempeh needs
- + Multi-use machine covers natto and sourdough proofing too
- - Large machine takes serious counter or cabinet space
- - Smart features add a learning curve for first uses
#2Kawachi's yellow koji starter spores, 0.53oz (15g) of tane-koji oryzae for miso, soy sauce and Japanese ferments.
Fit for the job 9/10 · Features and specs 8/10 · Build and materials 9/10 · Value 8/10
- + Yellow koji spores are the classic choice for miso and soy sauce
- + Kawachi is a long-established Japanese koji spore producer
- + 15g provides enough spores for several inoculations
- - Growing koji needs precise heat and humidity control
- - Spores are for making koji, so rice or barley must be prepared
#3Kawashimaya's natto starter powder, 3g (0.1oz) of Bacillus subtilis to make 10-30kg of homemade natto.
Fit for the job 9/10 · Features and specs 8/10 · Build and materials 8/10 · Value 9/10
- + 3g of powder makes 10-30kg of natto, a very high yield
- + Bacillus Subtilis from soybean extract is the classic natto culture
- + Tiny pack is easy to store in the fridge or freezer
- - Very small doses are hard to measure without a micro scoop
- - Natto needs careful temperature and humidity control
#4Hishiroku Kairyou Chohaku-kin koji spores in a 20 g powder sachet, sold by Kawashimaya. An Aspergillus oryzae starter for white rice koji, miso, amazake and sake.
Fit for the job 9/10 · Features and specs 8/10 · Build and materials 8/10 · Value 8/10
- + Made by Hishiroku of Kyoto, described in the listing as a 300-year-old specialist koji maker.
- + One 20 g sachet is rated to make up to 15 kg (33 lb) of rice koji, more than most home batches need.
- + Powder format lets you adjust the dose, and the listing suggests using 2 to 3 times more for better results.
- - Spores only: you still need steamed rice and a warm, humid incubation setup to grow koji.
- - A 20 g sachet is a lot for an occasional maker, so leftover spores need careful cool, dry storage.
#5Fermentaholics' jun kombucha starter culture with USDA certified organic jun SCOBY and starter tea, makes 1 Gallon.
Fit for the job 9/10 · Features and specs 8/10 · Build and materials 8/10 · Value 8/10
- + Jun SCOBY is adapted to green tea and honey, unlike standard kombucha cultures
- + Starter tea comes with it, giving the first gallon a protected start
- + USDA Certified Organic culture suits brewers seeking certified ingredients
- - Honey and green tea for jun cost more than sugar and black tea
- - No jar or cover included, so brewing gear must already be on hand
#6Fermentaholics Water Kefir Essentials Kit: organic water kefir grains plus a 1-quart wide mouth jar, breathable cover, mesh strainer, thermometer strip and pH strips. A complete beginner set.
Fit for the job 9/10 · Features and specs 8/10 · Build and materials 7/10 · Value 8/10
- + Grains and equipment in one box: 1-quart jar, breathable cover, rubber band, pipette and mesh strainer.
- + Adds an adhesive temperature strip, jar marker and pH test strips.
- + Listing says the grains are certified organic and Kosher, with step by step instructions.
- - A 1-quart jar makes a small batch, so heavy drinkers will want a larger one.
- - Costs more than buying grains alone, so it is best for newcomers without a jar and strainer.
#7GRANURA HOME's folding proofing box holds 50 to 130 F in 1 degree steps with three-sided 70 watt heating and a 0-99 hour timer or continuous mode, in a 16 x 12 x 12 inch space.
Fit for the job 8/10 · Features and specs 9/10 · Build and materials 7/10 · Value 8/10
- + 50 to 130 F range in 1 degree steps spans the warm settings used for tempeh, natto and yogurt as well as dough.
- + Timer runs to 99 hours or continuously, long enough for incubations that outlast a 24 hour timer.
- + Side-wall thermostat with a probe that reads the air, plus a top window and humidity gauge for a look inside.
- - The listing is written mainly around bread proofing, so tempeh makers set their own temperature and timing.
- - 16 x 12 x 12 inches is a real countertop footprint when open, though it folds flat for storage.
#8Kawashimaya's natto starter spores powder made from soybean extract, a 30g pack for homemade natto.
Fit for the job 9/10 · Features and specs 7/10 · Build and materials 8/10 · Value 8/10
- + 30g pack supplies many batches of homemade natto
- + Soybean Extract base keeps the starter aligned with traditional natto
- + Kawashimaya specializes in Japanese fermentation ingredients
- - Needs steady heat around a full day, so an incubator helps
- - Larger pack than casual natto makers are likely to use
#9Shirayuri koji (Aspergillus oryzae) spores, gluten-free and vegan, in a large 200g/8oz bag for heavy use.
Fit for the job 8/10 · Features and specs 7/10 · Build and materials 8/10 · Value 9/10
- + 200g bag supplies many batches for miso and shio koji makers
- + Shirayuri is a known strain for rice koji
- + Gluten-Free Vegan label suits plant-based kitchens
- - Large quantity may lose viability before a hobbyist uses it all
- - Bulk bag needs careful cold, dry storage
#10Yemoos' dried authentic ginger beer plant, a culture specialist's shelf-stable starter for traditional ginger beer.
Fit for the job 9/10 · Features and specs 6/10 · Build and materials 8/10 · Value 8/10
- + Authentic ginger beer plant is a true symbiotic culture, not just a yeast
- + Dried format stores until you are ready to activate and brew
- + Yemoos focuses on cultures, which suggests reliable handling
- - Dried cultures need patience and a few feedings before brewing strongly
- - Culture only, so ginger, sugar, jars and bottles are all extra
#11Japanese natto starter spores (nattomoto), 3g of 100% organic soybean extract, a product of Japan.
Fit for the job 8/10 · Features and specs 7/10 · Build and materials 8/10 · Value 8/10
- + 100% Organic soybean extract base suits organic kitchens
- + Product of Japan nattomoto uses a traditional starter
- + 3g pack goes a long way for many soybean batches
- - Compare seller ratings and feedback before choosing a supplier
- - Tiny doses need careful measuring for consistent natto
#12Shiragiku koji (Aspergillus oryzae) spores, gluten-free and vegan, in a 10g/0.35oz packet.
Fit for the job 8/10 · Features and specs 7/10 · Build and materials 8/10 · Value 7/10
- + Shiragiku strain is popular for sweet rice koji and amazake
- + Gluten-Free Vegan label suits plant-based fermenters
- + 10g size is a manageable amount for home experiments
- - Small packet is quickly used by frequent koji makers
- - Success depends on steady warm, humid incubation
#13Cultures For Health's natto starter spores for traditional Japanese soybean natto, gluten free and vegan.
Fit for the job 8/10 · Features and specs 7/10 · Build and materials 8/10 · Value 7/10
- + Cultures For Health offers detailed natto guides for beginners
- + Gluten Free Vegan spores suit plant-based fermenters
- + Traditional culture recreates the classic sticky natto texture
- - Confirm how many batches the spores cover before comparing prices
- - Natto aroma is strong and not everyone enjoys it
#14Fermentaholics Jun Kombucha Essentials Kit: organic Jun SCOBY with a 1-gallon glass jar, breathable cover, rubber band and thermometer strip. A stripped-down starter for Jun tea.
Fit for the job 8/10 · Features and specs 7/10 · Build and materials 7/10 · Value 8/10
- + Includes a Jun SCOBY and a 1-gallon glass brewing jar, so a first batch needs few extra items.
- + Comes with a muslin cover, rubber band and adhesive thermometer.
- + Listing describes it as the budget version of the brand's Jun kit.
- - No bottles, funnel or tea are listed, so you need those separately.
- - A 1-gallon batch is much bigger than the 1-quart culture it replaces.
#15Fermentaholics Complete Jun Kombucha Brewing Starter Kit with an organic SCOBY, billed as everything needed to brew Jun. A boxed option from a well known culture seller.
Fit for the job 8/10 · Features and specs 7/10 · Build and materials 7/10 · Value 8/10
- + Listed as a complete kit with step-by-step instructions and customer support.
- + Includes a USDA Certified Organic SCOBY.
- + Jun tea is described as having a fresh, crisp flavor.
- - The listing does not itemize the contents, so check the exact parts before buying.
- - Does not mention the swing top bottles of the kit it replaces.
#16Natural Probio's water kefir grains starter culture kit with a complete guide, recipes and tips for flavored ferments.
Fit for the job 8/10 · Features and specs 7/10 · Build and materials 7/10 · Value 8/10
- + Recipes and tips help move beyond plain sugar water to flavored sodas
- + Complete guide covers care of the grains between batches
- + Starter culture kit suits beginners who want written support
- - Ask the seller whether the grains are live or dried before ordering
- - No jar or strainer is mentioned, so extra equipment is needed
#17UMJIGF's 3.5L electric natto fermenter with smart panel control, adaptable for tempeh and other warm ferments.
Fit for the job 7/10 · Features and specs 8/10 · Build and materials 7/10 · Value 7/10
- + Smart Panel Control makes setting time and heat straightforward
- + 3.5L capacity handles family-size natto batches
- + Enclosed design holds humidity that natto and tempeh like
- - Deep container is less ideal for flat tempeh trays
- - Lesser-known brand offers limited detail on long-term reliability
#18Florida Sun Kefir live water kefir grains in a full portion cup, with step-by-step instructions and an online recipe PDF. A grains-only pick for an existing jar.
Fit for the job 8/10 · Features and specs 6/10 · Build and materials 7/10 · Value 8/10
- + Sold as live grains in a full portion cup, ready to start water kefir with sugar and water.
- + Listing includes step by step instructions and a downloadable PDF with recipes and care.
- + One of the lower-cost ways to start water kefir, since the listing sells only the grains.
- - Grains only: no jar, strainer or cover, so you need your own equipment.
- - Listing is heavy on marketing claims and light on the amount of grains.
#19A ginger bug probiotic soda starter with live dried cultures plus root beer and ginger beer recipes for homemade soda.
Fit for the job 7/10 · Features and specs 7/10 · Build and materials 7/10 · Value 8/10
- + Root beer and ginger beer recipes give two soda styles to start with
- + Live dried cultures skip the week of building a wild ginger bug
- + Probiotic soda approach suits families swapping out store-bought soda
- - Ginger bug starter is not the same as a true ginger beer plant culture
- - Root beer recipes need extra roots and spices that are not included
#20An automatic electric natto fermenter maker, a 3.5L stainless steel unit for natto, yogurt and tempeh.
Fit for the job 7/10 · Features and specs 7/10 · Build and materials 7/10 · Value 7/10
- + Stainless Steel inner pot is easy to clean after sticky natto
- + 3.5L size handles a household batch of natto or yogurt
- + Automatic heat control keeps ferments in a narrow warm range
- - Pot shape is better for natto than flat tempeh cakes
- - Check the specifications for the exact temperature range before buying
#21LynxLink's kefir starter kit pairs a 64 oz wide mouth glass jar and lid with a nylon fine mesh strainer for milk or water kefir and a stick-on thermometer. No grains are named in the title.
Fit for the job 7/10 · Features and specs 7/10 · Build and materials 7/10 · Value 7/10
- + BPA-free nylon mesh strainer, so the grains do not touch a metal strainer when you separate them.
- + 64 oz jar is double the size of a quart kit, enough for a household batch of water kefir in one brew.
- + Stick-on thermometer is included for keeping an eye on the temperature at the jar.
- - The title does not mention kefir grains, so budget for live or dehydrated grains on top of this kit.
- - Much of the listing copy is about kombucha, with little detail that is specific to water kefir.
#22A ginger beer plant kit for making your own ginger beer at home, a starter culture for traditional fizzy ginger soda.
Fit for the job 8/10 · Features and specs 5/10 · Build and materials 6/10 · Value 7/10
- + True ginger beer plant cultures can be reused for many batches
- + Kit framing gives beginners one purchase to start brewing ginger beer
- + Traditional culture makes a more complex brew than a quick yeast soda
- - Check the listing photos to confirm exactly what gear ships with it
- - Vague brand details make quality hard to judge from the listing
#23An authentic ginger beer plant culture, a plain listing for brewers who want the traditional symbiotic ginger beer starter.
Fit for the job 8/10 · Features and specs 5/10 · Build and materials 6/10 · Value 7/10
- + Reusable culture keeps producing batches when fed ginger and sugar
- + Authentic plant gives a traditional flavor rather than a yeast shortcut
- + Plain culture listing is simple if you already own jars and bottles
- - Look up a beginner guide online since the package may be light on steps
- - Listing gives no hint of whether culture is live or dried
#24A jun scoby with starter tea, a no-frills culture listing for brewers ready to ferment green tea and honey.
Fit for the job 7/10 · Features and specs 5/10 · Build and materials 6/10 · Value 6/10
- + Starter tea is included, which gives the culture an acidic head start
- + Culture-only listing works for brewers who already own jars and covers
- + Jun ferments quickly at moderate temperatures compared with kombucha
- - Very sparse title leaves batch size and origin unclear
- - Compare seller photos and ratings to judge quality before ordering
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Ferment Nest curates picks for US shoppers. Scores are our editorial assessment. We may earn a commission from links on this page.