Making mead above 18% ABV is entirely possible at home, but it requires more planning than a standard batch. The keys are choosing a yeast that can survive high alcohol levels, feeding honey in stages rather than all at once, and keeping your yeast healthy with proper nutrients and degassing throughout fermentation. Here’s how to put it all together.
Choose the Right Yeast
Not all yeast can survive in high-alcohol environments. Most bread yeast and many ale yeasts die off around 12-14% ABV, leaving behind unfermented sugar and a stuck batch. For high-gravity mead, you need a strain rated for at least 18% tolerance. Wyeast 4946, specifically designed for bold, high-alcohol fermentation, tolerates up to 18% ABV. Lalvin EC-1118 (a champagne yeast) is another popular choice with similar tolerance, and it ferments aggressively and dry. If you want to push past 20%, Lalvin 1118 paired with step feeding is the most reliable path.
Your yeast choice also shapes the final flavor. Champagne yeasts ferment very clean but strip out some of the honey character. Wine yeasts like Lalvin 71B produce a fruitier, rounder mead but typically top out around 14-16%. For maximum ABV, prioritize alcohol tolerance over flavor contribution. You can always add complexity through honey variety and aging.
Rehydrate Yeast Properly
High-gravity musts put enormous osmotic pressure on yeast cells. Pitching dry yeast straight into a concentrated honey solution kills a large percentage of the cells before they even start working. Rehydrating with a nutrient like Go-Ferm gives the yeast a much better survival rate and stronger fermentation from the start.
The process is straightforward: mix Go-Ferm into water at about 110°F (43°C) using a ratio of 1 part yeast to 1.25 parts Go-Ferm by weight. For a typical 5-gallon batch using one 5-gram packet of yeast, that’s roughly 6.25 grams of Go-Ferm dissolved in 20 times its weight in warm water. Let the yeast sit in this solution for 15-20 minutes before pitching. This step alone can be the difference between a clean fermentation and a stall.
Start With a Lower Gravity
The biggest mistake in high-ABV mead is dumping all your honey in on day one. A starting gravity of 1.150 or higher creates so much sugar pressure that yeast struggle to reproduce, ferment slowly, and produce harsh fusel alcohols. Instead, start with a moderate concentration, around 20% sugar in your solution, and add honey in stages as the yeast consume it.
Honey is roughly 75% sugar by weight. For a 5-gallon batch aiming for 20%+ ABV, you might use 18-22 pounds of honey total, but only add about a third at the start. This gives you a starting gravity around 1.080-1.090, which is comfortable territory for yeast to multiply quickly and establish a strong colony. Leave at least a third of your fermenter’s volume empty to accommodate later honey additions and the vigorous foaming that comes with active fermentation.
Step Feed the Remaining Honey
Once your initial sugar ferments down (typically 1-2 weeks, confirmed by a hydrometer reading near 1.000), add the next third of your honey. A practical method: scoop out some of the fermenting must, about twice the volume of honey you’re adding, and dissolve the honey into it in a separate container. This avoids dumping thick, cold honey into your fermenter where it sinks to the bottom and won’t mix evenly. Stir gently to dissolve without splashing in too much oxygen at this stage.
When that addition ferments out, add the final portion. With each successive addition, reduce the amount slightly. As alcohol levels climb past 14-15%, the yeast slow down considerably, and smaller sugar additions prevent overwhelming them. One experienced meadmaker targeting 20%+ described using three equal honey additions with nutrients at each stage, timed by monitoring when half the sugar from each addition had been consumed. The final addition should be small enough that the yeast can finish it before hitting their alcohol tolerance wall.
Follow a Staggered Nutrient Schedule
Honey is almost pure sugar with very little nitrogen, which yeast need to build proteins and stay healthy. Without supplemental nitrogen in the range of 300-500 mg/L, fermentation stalls and off-flavors develop. The standard approach uses two products together: diammonium phosphate (DAP) for inorganic nitrogen, and a blended nutrient like Fermaid-K that provides organic nitrogen plus vitamins and minerals.
A proven schedule for a 5-gallon batch:
- Day 0: After pitching rehydrated yeast, add 4.5g Fermaid-K and 2g DAP
- Day 2: Gently stir, then add 4.5g Fermaid-K and 2g DAP
- Day 4: Repeat the same addition with stirring
- Day 6: Final addition of 4.5g Fermaid-K and 2g DAP
When step feeding honey, add a proportional nutrient dose alongside each honey addition as well. Stop adding DAP once the ABV reaches roughly 9-10%, because yeast lose the ability to absorb inorganic nitrogen at higher alcohol levels. Organic nutrients from Fermaid-K remain useful longer into the ferment.
Degas Twice Daily During Active Fermentation
Carbon dioxide dissolved in the must is mildly toxic to yeast and slows fermentation. In a high-gravity environment where yeast are already stressed, this extra burden can push a ferment into a stall. Modern meadmakers degas twice a day during active fermentation using a wine whip attached to an electric drill. Insert the whip and stir near the surface for one to two minutes, driving CO2 out of solution.
During the first few days, this also serves as aeration. Yeast need oxygen early on to build strong cell membranes that help them survive rising alcohol levels. Vigorous stirring near the surface pulls oxygen into the must. After about the first third of sugar has been consumed (roughly day 3-4 for a standard start), switch to gentler degassing to avoid introducing oxygen, which can cause oxidation flavors in the finished mead. Continue degassing until roughly two-thirds of the total sugar has fermented away.
Keep pH Above 3.0
As fermentation progresses, acids produced by the yeast lower the pH of your must. If it drops below 3.0, most yeast strains struggle or stall completely. This is one of the more common causes of stuck high-gravity ferments that meadmakers don’t think to check.
A target pH of 3.2-3.5 gives you a comfortable buffer. If your pH drops too low, potassium bicarbonate raises it gently. Add small amounts, dissolve, test, and repeat until you’re back in range. Keep in mind that pH will continue falling as fermentation progresses, so checking periodically with pH strips or a meter is worth the effort, especially after each honey addition when fermentation activity picks up again.
Control Temperature Strictly
High fermentation temperatures dramatically increase the production of fusel alcohols, the harsh, hot, solvent-like flavors that plague strong meads. Research shows fusel alcohol production increases markedly even across a relatively small temperature range, from 50°F to 59°F in one study. Higher temperatures also increase ester production, which can make a mead taste overly fruity or nail-polish-like at extreme levels.
For most high-gravity meads, keep fermentation temperature between 60-68°F (15-20°C), depending on your yeast strain’s preferred range. Cooler is generally better for clean flavor, though too cold will slow fermentation to a crawl. Consistency matters as much as the temperature itself. Raising the temperature mid-ferment produces fewer fusels than running the whole ferment warm, so if your mead stalls near the end, a gentle temperature bump to 70°F can coax the yeast to finish without creating as many off-flavors as a consistently warm ferment would.
Aging Is Not Optional
A freshly fermented 18-20% mead will taste rough. The alcohol will be hot and sharp, flavors will be disjointed, and the honey character may be buried under harsh notes. High-ABV meads need 12-24 months of aging to reach their potential, with flavors peaking around the 2-year mark. This isn’t a suggestion you can skip. The difference between a 3-month-old and an 18-month-old sack mead is dramatic.
Once fermentation is completely finished (stable gravity readings over two weeks), rack into a secondary vessel with minimal headspace. If you plan to backsweeten with additional honey, stabilize first using potassium sorbate and potassium metabisulfite together. Sorbate alone won’t reliably prevent refermentation at high ABV, and skipping stabilization before adding sugar risks bottle bombs. Store your aging mead in a cool, dark place and resist the urge to open it early. Patience is the single most important ingredient in a great high-ABV mead.