Fort Point is the only brewery in the world making beer out of fresh Lobos Creek water — a unique natural resource right in San Francisco’s backyard.
Water is the foundation of a great-tasting beer. Since beer is up to 96 percent water, a brewery’s water source contributes an essential mix of minerals that affect the mashing and fermenting processes, and ultimately shapes the taste of the final product.
We already knew that San Francisco had some of the best-tasting water in the world. But when Fort Point Beer Company decided to open our headquarters in the Presidio, we soon discovered we wouldn’t be using San Francisco’s municipal water supply after all. Even better: we had a serendipitous resource in our own backyard — Lobos Creek.
We learned that while other creeks were moved underground or diverted over the years as the city developed, Lobos Creek is the last stream that flows freely within San Francisco city limits. Dan Patrick, the water treatment plant supervisor at the Presidio Trust, explained more as he walked us through the course of the creek: it flows up from an aquifer at 15th Ave, runs one mile through the Presidio, and drains out onto the southern section of Baker Beach. At the end of the stream lies the Presidio Water Treatment Plant — an organization run by Dan and his team of eight — that cleans and cultivates over 1.5 million gallons of fresh water daily. They distribute it from the creek across the park for use by the more than 100 businesses, visitors, and 3,000 residents that call the area home.
Needless to say, Lobos Creek water is an undeniable treasure for many people, and a historically protected one at that. But it also turned out to be great for our brewing needs.
“When we moved into the brewery we had a rough idea of what the water was like, but didn’t have exact figures,” says head brewer Mike Schnebeck. “I knew at worst we’d be looking at extra equipment to get the water to the right mineral levels where we wanted it. When the report came back from the lab, I was stoked — we didn’t need to change a thing.”
The results were clear: Lobos Creek water was an ideal blend; there was no need to perform the intensive process of stripping it down and adding back in minerals. As is, Lobos Creek water provides a balanced mineral content and a touch of hardness, adding a crisp, bright mouthfeel, but also a great foundation that’s easy to adjust for various styles. You might compare it to historical London water profiles, like those used for an English Bitter-style beer.
But what exactly makes it taste so good? Four important water qualities brewers consider when brewing beer are pH, alkalinity, calcium, and the sulfate-chloride ratio. Here’s a breakdown of how each affects the brewing process:
- The pH of the water directly affects the wort during mashing, changing the fermentability, color, clarity, and taste of the wort and beer — brewers usually try and get the mash water to a desired pH of 5.2 to 5.4, which in turn helps keep the pH of beer in the 4 to 4.5 range.
- Alkalinity is a concentration of carbonate (CO3), bicarbonate (HCO3), and hydroxyl (OH-) ions in water that can affect the pH. With higher alkalinity water, more acid will be required to keep the pH in the right range for mashing and flavor balance.
- The biggest impact of calcium is on the hardness of the water. Higher concentrations of calcium or magnesium produces hard water while lower concentrations create soft water. Both hard and soft water can be used for brewing different beer styles as long as alkalinity levels are appropriate. Calcium plays an important role in facilitating various yeast and enzymatic reactions throughout the brewing process.
- The sulfate-chloride ratio is key to the overall taste and mouthfeel of the beer. Chloride enhances malt flavors resulting in fuller, sweeter beers while improving beer stability and clarity. Sulfates, on the other hand, accentuate hop flavors to create a drier and more bitter taste. (Sulfates are not to be confused with sulfites, a preservative typically used in wine).
For us, the calcium levels are high enough to ensure yeast health, while the sulfates and chlorides are balanced to deliver that pleasant mouthfeel.
During the Fort Point Beer Company brewing process, the Lobos Creek water composition performs well at various stages, including the mashing process where water and grains are heated to extract sugars. The water also ended up being versatile and favorable for a wide variety of beer types.
Of course, we tweak the components a little bit for each type of beer. KSA receives no extra salt additions, keeping it crisp with slight minerality, whereas Westfalia receives a small dose of calcium chloride, helping to accentuate the malt flavors and smooth out the mouthfeel. Animal is dosed with both gypsum and calcium chloride — the extra sulfate in gypsum helps the hop character pop, but the overall sulfate-chloride ratio leans toward chloride, making the beer’s mouthfeel a bit softer and rounder.
In general, municipal water sources can vary greatly depending on the season, weather and a variety of other factors. It makes sense that the mineral composition of San Francisco’s water supply is constantly evolving; it reflects changes in surface water and groundwater sources, through dry and wet periods. The city’s tap water might taste great year-round. But being the only brewery in the world to use Lobos Creek water gives us something special: thanks to our stable, consistent water source, we’re able to deliver a perfectly balanced and dependably enjoyable beer.