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Soul of Beer
Anyone with this link can view this fermentation (read-only). No account needed.
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Privacy Policy
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Using the app from your home screen? Then your iPhone opens the link in Safari, not here. So don't tap the button in the email – press and hold it, choose Copy Link, and tap here:
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It keeps your custom profiles, house strains and tasting cards, so you can reach them from all your devices.
Enter ID from the OLED menu
Action-meny -> Device ID
After activating: restart the device within an hour so it can collect its key. Missed it? Just press Activate again.
Search or filter more than 70 strains, and open a card for temperature guide, flavour profile and equivalents.
What you save lives only in this browser.
Pick a strain and drag the points to shape your fermentation's temperature curve. Save, and the profile lands in the Yeast Library.
Turn your phone
The curve needs the full width. Screen not turning? Switch off rotation lock.
The profile handles temperature. Remember that pitch rate and OG also affect how long fermentation takes — use the device controls to extend or shorten phases as needed.
Put Soul of Beer on your home screen and open it as an app of its own.
Already on your home screen? Open it from there.
Enable push notifications to receive alerts on your phone regarding temperature fluctuations, power outages, or when it's time to dry hop.
YeastMaster v1.0.4
Privacy Policy
Last updated: 26 October 2026
Soul of Beer (soulof.beer) is a web app for homebrewers: lessons, tools, a yeast library, tasting cards, games and fermentation monitoring with the YeastMaster unit. The service is run by AY Tech. If you have questions about your personal data, write to info@soulof.beer.
Most of Soul of Beer works without an account. Then what you do – your own yeasts and profiles, tasting cards, triangle tests, game records and settings – is stored only in your own browser. We don"t see it, and it doesn"t leave your device unless you share a link yourself.
When you sign in, connect a YeastMaster unit or send us something yourself, we store:
The data is used to provide what you asked for: signing you in, storing your library and your units, showing the fermentation live, sending the alerts you chose and replying when you write to us. Google Analytics only runs if you have said yes. Backups and protection against abuse are there so the service can be relied on. We don"t sell your data and don"t share it for marketing.
Sign-in is handled by Google Firebase Authentication. Your library, your units and fermentation data are stored in a database at MongoDB Atlas. The app and the server run at Render, which – like any web server – logs technical details about requests, such as IP addresses. Push notifications go through your browser"s push service. Messages from Report Bug and Suggest Idea go through Formspree, and sign-in links and the welcome email are sent through Resend. The fonts are loaded from Google Fonts and the map in the yeast library from OpenStreetMap, and they see your IP address when the page loads them. Several of these providers are based in the USA, so data may be processed outside the EU/EEA.
The database is backed up, encrypted, every night, and each copy is kept for 30 days. If you delete your account, your data therefore remains in the backups for at most 30 days before it disappears. The backups are only used to restore the service if something breaks.
You can create a link that shows a running fermentation to anyone, with no sign-in. It shows the fermentation data (temperature, phase, yeast strain, profile name), not your email address or your library. Anyone with the link can open it and pass it on without you seeing it. You can switch sharing off whenever you like, and the link then stops working. If you share a triangle test, the result – number of tasters, number correct and the names you gave the beers – is in the link itself. We don"t store it.
For as long as you have an account. When you delete your account, your library, your units, your history and the account itself are removed. One exception: if someone else still has the same YeastMaster unit connected to their account, the unit"s fermentation logs are kept so their history doesn"t disappear with your account. An address on the waitlist is used for a single email when the unit can be bought, and is then deleted. If you want it removed sooner, write to info@soulof.beer.
Under the GDPR you have the right to know what data we hold about you, to have it corrected or deleted, and to withdraw a consent. You delete it yourself in the app under Settings → Delete account and all data, and you change your analytics choice under Settings too. For anything else, write to info@soulof.beer. If you think we handle your data wrongly, you can complain to the data protection authority in your country (in Sweden: IMY).
The browser"s local storage is used to remember your sign-in, your language, temperature and gravity units, theme, a guided session in progress and the sound setting in the games – and, without an account, your library, your tasting cards, triangle tests and game records. It stays in your browser. Google Analytics (a Google service) is used to understand how the app is used and which countries visitors come from. It sets cookies and collects, among other things, approximate location (derived from the IP address), device and browser type and events in the app, and that data is processed by Google. Analytics only runs if you say yes, and you can change your choice at any time under Settings. We don"t use advertising cookies.
Yeast – the soul of beer
For homebrewers who want to get to know their yeast — from the first starter to a freezer bank of their own.
Not to get too poetic about it, but we believe the true soul of beer lives within the yeast. As the old brewing adage goes: "The brewer makes wort, but the yeast makes beer." It's fascinating how these microscopic artisans transform a simple, sweet liquid into the complex, soulful drink we call beer.
Soul of Beer is a tribute to this biological magic, and a workshop for anyone who wants to work with it. The tools below are free and run right in your browser — no account needed to start.
Learn to handle yeast, plan your fermentation and try things yourself, right in your browser.
Step-by-step lessons with animated figures: starters, cell counting, viability, catching wild yeast and preserving strains.
Printable bench protocols for agar plates and slants, harvesting yeast, a glycerol freezer bank and a strain library you keep alive.
Pitch rate, alcohol, carbonation, refractometer, strike water, keg line balancing and cell counting, and for the tasting: triangle test and tasting cards.
Over 70 commercial strains with temperature guides, flavour profiles and equivalents across the labs.
Draw your fermentation's temperature curve day by day, from pitch to cold crash. Profiles are saved in your browser — or in the cloud with an account.
Not sure where to begin?
Create a free account to keep your library and profiles in the cloud. Log in or sign up →
The unit that runs your profiles for you: it sits by the fermentation fridge, drives cooling and heating along the curve you drew, and lets you follow the fermentation live in the app. The hardware is in development.
A controller with an OLED display, a dial and two temperature sensors. It switches the fridge and the heater through wireless smart plugs you buy yourself, so they fit your country's sockets.
Follow the temperature curve and the profile's phase in real time, wherever you are.
Want to know when the unit can be bought? Join the waiting list →
YeastMaster is built around a custom ESP32 brain, designed to sit seamlessly on your fermentation chamber. It operates 100% locally, meaning your beer is safe even if the WiFi drops.
A high-contrast OLED screen paired with a tactile rotary encoder gives you a classic, laboratory-grade interface. Adjust offsets, change yeast profiles, or trigger a cold crash right at the fridge.
Precision requires data. YeastMaster uses two detachable, waterproof sensors. One measures the ambient air in the fridge, while the other sits directly in the beer (or taped to the fermenter), allowing the dual-sensor logic to prevent massive temperature swings.
No dangerous high-voltage wiring. YeastMaster controls self-learning smart plugs over 433 MHz radio: one for the fridge or freezer and one for the heat, such as a heat mat. The plugs aren't included: you buy them yourself so they fit your country's sockets, and they're often sold in packs with a remote.
The fridge isn't modified, it simply gets power or doesn't, so nearly every fridge and freezer with an ordinary plug works. Turn its own thermostat to the coldest setting. The exception is a fridge with a digital panel that comes back in standby after a power cut. The compressor is protected: after each cooling stop it rests for at least five minutes.
Want to know when the unit can be bought? Join the waiting list →
You're already a microbiologist. Let's set up your kitchen lab and start harvesting liquid gold.
Tvätta jästkakan och skörda "flytande guld" (slurry).
Wake up your yeast and ensure a healthy fermentation.
Why magnetic vortexes are a brewer's best friend.
Using microscopes and haemocytometers like a pro.
Alive isn't the same as healthy — and why it matters.
What to buy — and what can wait.
Learn to pour, streak, and isolate pure strains.
Glycerol in the freezer: keep a strain for years instead of weeks.
Hunt for local microbes and brew something unique.
Cooling, heating and probes — you set the temperature, not the room.
Varför profilen är en startpunkt, inte ett löfte.
Rädda din öl från smörsmaken.
Kristallklart resultat på 48 timmar.
Ale or lager, off-flavours, lab kit and beer colour – as games.
Exact, printable bench protocols for serious kitchen-lab routines.
Calculators for the numbers that decide a fermentation.
Calculate optimal pitch rates and starter steps.
Count cells in the haemocytometer and get density and viability.
OG and FG give ABV and attenuation, with temperature correction for your hydrometer.
Priming sugar per bottle or keg pressure for the carbonation you want.
Turn Brix into OG and FG, even after fermentation has started.
How hot the water should be for the mash to land on the right temperature.
How long the beer line should be for a calm pour without foam.
Blind-taste two beers and find out whether the difference can really be tasted.
Score your beers the way judges do, and see what each yeast and profile gave you.
Test your yeast know-how and play with your tasting cards.
Welcome to the LIVE VIEW!
This is your digital command center. Once your YeastMaster is connected, you can monitor your active fermentation in real-time, from anywhere in the world.
All vital stats are streamed directly to this dashboard, giving you total control and peace of mind.
Want a quick tour of the interface?
Ales often land at 70–80 % apparent attenuation. A warm mash, crystal malt or extract gives less, sugar more. Fermentation is done when the gravity holds steady for 2–3 days, not when it hits a particular number.
The warmest the beer got after fermentation finished, often the diacetyl rest. Warmer beer has let more CO₂ go. Take it from the Profiler
Only bottle once the gravity has held steady for several days: if the beer is still fermenting, the carbonation ends up higher than calculated.
Measure the same wort once with a hydrometer and the refractometer: WCF = Brix ÷ °P. Usually 1.02–1.06.
Once fermentation has started, the alcohol makes the refractometer read too high. The correction follows Terrill's formula; allow ±0.002 and check the FG with a hydrometer when it matters.
A cold cooler that hasn't been preheated takes a few degrees: add 1–2 °C. Heating the water in the same vessel (BIAB, all-in-one): 0.
Stir well and check after five minutes; nudge with hot or cold water. 63–65 °C gives a drier beer, 68–70 °C a fuller one.
Carbonation needs a certain pressure in the keg, but that same pressure would shoot the beer out of the tap as foam. Two things slow the beer down on its way: the line, and the height if the tap sits above the keg, since the beer then has to be lifted. With the right line length the pressure is used up by the time the beer reaches the tap, and it pours calmly into the glass.
From the middle of the keg up to the tap. Tap lower than the keg: a negative number.
A starting length: resistance varies between makes, and barrier line differs from vinyl, so use the manufacturer’s value if there is one. Cut it long: a line can be shortened, never lengthened. Still foaming? First check that the line is as cold as the beer.
A triangle test shows whether a difference between two beers can be tasted: each taster gets three glasses, two of one beer and one of the other, and tries to pick out the odd one.
Tip: at least 10 tasters gives a result you can trust. With fewer, the test can rarely show a difference, even if there is one.
Mixed the sample 1:1 with methylene blue? Then the dilution doubles: 1:100 becomes 1:200 (choose Other).
With a YeastMaster you pick up to 10 strains here and sync them — with their temperature profiles — to the unit in one go. The unit is in development.
Dina idéer och buggrapporter hjälper oss att brygga en bättre app!
Tack för din feedback. Vi hörs snart!
Catalog your wild captures, house blends, or local yeast strains.
Count up one step every time you grow it on.
The place is rounded to about a kilometre, so nobody can see exactly where you live.
You learn this after a few brews. Leave it empty until then.
Decides whether the strain suits a pale lager or a saison.
Sourness means there are bacteria in the culture, unless that was the plan.
The temperature you last fermented at. The range emerges with more brews.
Turn your phone upright
YeastMaster is made for portrait. Only the Profiler’s full screen goes sideways.