Gruit, Sahti, and Herbal Ales: Brewing Beer Like It's 1387

I once asked a homebrewer what he thought beer tasted like before hops, and he said, “Probably bad.” Most of us have been trained to think bitterness only comes from the floral punch of modern hops.

However, hops didn’t dominate European brewing until the 1500s. Before that, brewers used herbs, tree branches, and swamp plants to balance sweetness and prevent spoilage.

I didn’t believe this until I brewed my first sahti. I laid juniper branches across a bucket, poured hot wort through them, and pitched grocery store baker’s yeast.

Three days later, I had a beer that tasted like banana bread soaked in pine resin. It was strange, ancient, and absolutely alive.

This guide is about brewing before the hop monopoly. You will learn how to make sahti, how to use medieval gruit blends, and how to forage botanicals without poisoning yourself.

The Nordic Tradition: Sahti and the Juniper Filter Bed

Sahti is a Finnish farmhouse ale brewed the same way for centuries. It ignores hops and commercial brewer’s yeast in favor of juniper branches and farmstead fermentation.

The branches act as a natural filter bed during the lauter. This process infuses the wort with resinous, piney flavors that provide the primary “bitterness” of the style.

For a five-gallon batch, a four-to-six-inch layer of loosely packed branches is the technical sweet spot. Using too much makes the beer taste like a wreath, while too little loses the style’s defining character.

Traditionally, Finnish brewers used whatever yeast was available, often bread yeast. Baker’s yeast (Saccharomyces cerevisiae) ferments rapidly and produces massive amounts of banana and clove esters at warm temperatures.

I pitch one packet of active dry baker’s yeast and the beer is often drinkable in three to five days. It does not age well; you drink it fresh at cellar temperature.

The Bittering Trio: Yarrow, Mugwort, and Marsh Rosemary

Before hops, brewers used a blend called gruit. The most common plants were yarrow, mugwort, and marsh rosemary (bog myrtle), which provided aroma and mild preservation.

Yarrow offers a floral, medicinal bitterness similar to chamomile. Mugwort is more assertive, tasting green and earthy with a faint lingering sweetness.

Marsh rosemary is the powerhouse of the blend. It is intensely aromatic and minty, with a bitterness that can easily become overpowering if not dosed correctly.

Gruit does not preserve beer like hops do. Without the antimicrobial properties of hop alpha acids, these beers often sour within a week or two.

I treat gruit batches like fresh milk. They stay in the fridge and are consumed within seven days to avoid unintended acidification from wild bacteria.

Preservative Properties: Why Hops Won

Hops took over because they work. They are antimicrobial, they stabilize foam, and they allow beer to travel without spoiling.

A hopped IPA can sit for months, but a gruit ale starts to turn within days. Wild bacteria like Lactobacillus quickly take over gruit beers because the herbs lack the “kill switch” provided by hop resins.

Treat your gruit experiments as fresh products. Do not expect shelf stability unless you significantly increase the alcohol content to act as a secondary preservative.

Foraging Safety and Botanical Identification

Foraging for brewing botanicals is high-stakes work. Misidentifying a plant can lead to hospitalization or worse.

Yarrow (Achillea millefolium) is common but can be confused with poison hemlock. Hemlock has smooth, hairless stems with purple spots, while yarrow has fuzzy stems and no spots.

Mugwort (Artemisia vulgaris) has leaves that are dark green on top and silvery-white underneath. It smells strongly of sage.

Juniper (Juniperus communis) is a shrub with blue berries. Never confuse it with yew, which has red berries and is extremely poisonous.

Balancing Sweetness with Tannins

Hops provide the bitterness needed to cut through malt sugar. Gruit herbs are softer, meaning the beer can often taste cloying or like “liquid bread.”

The solution is to use tannins from tree bark or leaves to provide astringency. This dries out the mouthfeel, similar to over-steeped tea.

I use oak leaves or juniper bark in the boil to add structure. I also adjust the grain bill to include more pale malt and less crystal malt to ensure a drier finish.

Conclusion

Brewing gruit or sahti is an act of brewing archaeology. It reminds us that beer is tied to the land and the local seasons.

These beers are not IPA-replacements. They are strange, herbal windows into a time when brewing was dictated by the plants growing in the local meadow.

Start with a simple sahti. Use grocery store juniper and baker’s yeast. Take notes and expect it to taste like history.

References

• Buhner, S. H. (1998). Sacred and Herbal Healing Beers. Brewers Publications.
• Garshol, L. M. (2020). Historical Brewing Techniques. Brewers Publications.
• LaPensée, Clive. The Historical Companion to House-Brewing. Montagud Editores, 1990.
• Oregon State University. Juniperus communis and Toxicity. OSU Extension Service, 2021.