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3354 Coffey Ln Ste A
Santa Rosa
CA, 95403
United States
Jacob Quint

Our Philosophy

Gravity Wine House is a Santa Rosa-based, boutique, custom-crush facility. We work with a limited number of select winery clients, focusing on small lots of premium wine. Our goal is to make our winery clients feel like they are in their own, dedicated winery.

Our Facility

Attention to detail is the name of the game. We utilize top of the line equipment and infrastructure to make your wine—one hand-sorted cluster at a time.

If you would like to make an appointment to tour the facility or explore becoming a future custom crush client, please visit our website at We look forward to connecting with you.


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News Archive

Wine Production: Barrel Selections for Your Wine
29 May, 2019

Despite a history stretching back two millennia, barrels remain some of the most complex and misunderstood elements used in winemaking. In order to obtain a barrel that matches your desired style, it is important to understand and evaluate the numerous options available. In this article, we will delve deeper than the classic American versus French debate and explore how other properties and factors can influence the wine, while checking the validity of popular anecdotes.

To get started, let’s review how wood flavors can affect your end product. Oak storage can impact wine in several ways, but two are particularly significant: first, it allows a small amount of oxygen to interact with the wine, and second, it contributes aroma compounds that can alter the flavor. The amount of oxygen that moves into the wine is largely dictated by the wood grain; generally, the tighter the wood grain, the more oxygen you can expect to interact with the wine inside of the barrel. This interaction can be beneficial for certain types of wine, particularly red wines and richer white wines. Oak also has a standard set of flavors that it tends to impart on wine. These flavors are affected by the oak species, location of growth (even within the same forest), seasoning, and toasting. Some of the main compounds responsible for these aromas are shown in the table below.

When discussing barrels, the most frequently used descriptor is the provenance of the oak. There is a widespread notion that American oak is more aromatic and French oak is subtler but lends more tannin. Hungarian oak, which has been increasing in popularity, is said to fall somewhere in the middle. However, those assumptions are not always true. American oak usually refers to the species Q. alba. Meanwhile, there are two French oak species used in cooperage: Quercus robur and Q. petraea. Q. robur has coarser (wider) grain and typically lower concentrations of aroma compounds than Q. petraea, making the former better suited for aging spirits and the latter more complimentary to wine. Certain French forests grow one species or another, however many have a combination of both. Therefore, when we talk about American or French oak, it is important to note that we are discussing a difference in species as well as environmental growing conditions. The distinction between the two French species is, unfortunately, not well addressed (or sometimes confused) in non-academic and academic publications alike, leading to many of the misconceptions we have today.

When people state that American oak is more “aromatic” than French, this is typically attributed to the cis-oak lactone compound that lends a woody/coconut/sweet aroma. There is also a trans- isomer, however it has a low odor impact, so most people focus on the cis- portion when discussing lactones. There have been multiple studies comparing the relative concentrations of cis-oak lactone between the oak species, yet they are they are not always in agreement. While American oak is purported to have higher levels of cis-oak lactone than French, this is only definitively proven in comparison to the Q. robur species. While there is a lot of tree-to-tree variation in Q. alba, Q. petraea shows even higher levels of variability, and that makes comparing the two species challenging. In one study, total content of oak lactones in six Q. petraea trees from Tronçais ranged between ~1-78 μg/g (dry wood), while six Q. alba from Missouri and Virginia ranged from ~24-77 μg/g (Masson et al. 1995). The table shown below illustrates just how much variation there can be.

What all of this means is that the probability of an American oak barrel having those lactone aromas is higher than a French one. However, it is altogether possible to purchase a French oak (Q. petraea, specifically) barrel that actually has more oaky character than American! This underlines the importance of tasting through individual barrels during the winemaking progress, as this variation and unpredictability can lead to very different flavors in your wine.

While the “oak flavor” debate remains hazy, there are important differences between American and French oak that have been successfully quantified. One of them doesn’t require a science experiment to figure out: pricing. French oak barrels are typically the most expensive, followed by American, and then Hungarian are the most affordable. While some of this has to do with demand (currently, Hungarian oak doesn’t carry the same prestige as French), it is also due to physiological differences between European and American oak species. The internal structure of American oak allows it to be sawn into staves, while European oak must be split along the grain in order to be watertight. The need to split European logs translates into only 25% of it being available for stave production, while American logs can yield 50% (Chatonnet and Dubourdieu, 1998). As you might expect, this greatly increases the cost of French oak.

The physiological differences between the species also include a trait referred to as “grain”. Grain describes the width between growth rings, with “coarse” meaning larger and “fine/tight” indicating smaller. American oak typically grows faster than the French Q. petraea, which results in coarser grain. Interestingly, Q. robur, the other French species, also has coarse grain. There is a widely circulated belief that grain directly impacts the aroma intensity of wine, however this theory has been disproved. Studies have failed to show any correlation between grain size and sensory descriptors or levels of oak lactone. Rather, Sauvageot and Feuillat (1999) suggest the anecdotal reports of grain impact can actually be explained by species, e.g., when comparing coarse-grained Q. robur and tight-grained Q. petraea, which we’ve discussed as having very different concentrations of oak lactones. Although grain doesn’t influence the level of aroma compounds are imparted on the wine, it does affect how much oxygen enters. Somewhat counter-intuitively, tight-grained oak is more porous than coarse grain, and will therefore allow more oxygen ingress. This can be an important factor to take into account when choosing barrels for your desired style.

Examples of tight grain (left) and coarse/wide grain (right) in barrel staves. Wood grain in tree growth is influenced by several factors and has significant impact on the wood as a storage vessel. 

All oak barrels allow small amounts of oxygen to interact with the wine as it ages. These minute levels of oxygen can provide significant benefits during aging, especially for red wines. In fact, the presence of oxygen is required for essential chemical reactions that stabilize the wine’s color. For example, anthocyanins, color molecules that are susceptible to the color-loss process known as “bleaching,” react with tannin in the presence of oxygen to form much more stable color molecules, polymeric pigments. Oxygen can also impact the tannins by speeding up the rate at which they bind to one other. This binding and transformation process results in tannins that consumers perceive as being “smoother,” rather than more astringent.

The permeability of the wood that allows oxygen to move into the wine also allows water and ethanol to evaporate out of it. Depending on the humidity level where the barrels are stored, this can cause the percentage of alcohol in the wine to increase or decrease, sometimes dramatically. The loss of “wine” (technically just water and ethanol) through this process—colloquially referred to as the “angels’ share”—can impact more than just the alcohol percentage. The loss of water and ethanol can help to increase the concentration of flavor and aroma compounds, since they are too large to pass through the oak. As discussed above, choice of wood grain can help direct how much these changes will occur, and can therefore impact the final product.

The coopering and toasting of barrels involves a very controlled amount of fire inside the barrel. 

Another significant feature that can be selected is the toast level of the barrel. The interiors of barrels are usually toasted to bring particular flavors to the wine by caramelizing the barrel’s internal surface. This process breaks down the wood’s natural carbohydrates and lignins to create aromatic compounds. Typically, the greater the toast level, the lower the concentration of lactones. On the other hand, the lower the toast level, the more the amount of tannins are present, which can sometimes present a more astringent or bitter taste, or provide structure. Each flavor compound follows its own pattern with toasting: some are increased with toast, some are decreased, and others peak somewhere in the middle and then fall off. The most common, however, is for a compound reach a peak at a medium toast, and then when it passes a certain toast level, the aroma compounds begin to break down. It should be noted that many experiments on toast level have shown conflicting results, so these trends should certainly not be considered hard rules. 

Despite their ubiquitous use and very lengthy history, oak barrels remain one of the least understood aspects in winemaking. This is, in part, due to the nature of nature: barrels are made from living things and therefore exhibit a high level of variability. The inconsistency in raw wood is high to begin with, but there are so many steps that occur between tree and barrel that can cause a cascade of effects. With the difficulty of accounting for all of this variability, the scientific community has struggled to agree on how a particular barrel will affect a wine. This gap in knowledge has left a lot of space for anecdotal “evidence” to become widespread and accepted, despite it often being directly opposed to what scientific evidence we do have. To have the best chance of obtaining your desired oak style, it’s important to sort the fact from the fiction. 

An oak tree grove. Oak is a wood commonly used to make wine barrels (Photo courtesy of Forest Preserves of Cook County) 


Chatonnet, P. 1991. Incidences du bois de chêne sur la composition chimique et les qualités organoleptiques des vins. Applications technologiques. Mémoire de DER, Institut d’Oenologie, Université de Bordeaux II.

Chatonnet, P., and D. Dubourdie. 1998. Comparative study of the characteristics of American white oak (Quercus alba)and European oak Quercus petraea and Q. robur) for production of barrels used in barrel aging of wines. Am. J. Enol. Vitic. 49:79-85.

Feuillat, F., L. Moio, E. Guichard, M. Marinov, N. Fournier, and J.-L. Puech. 1997. Variation in the concentration of ellagitannins and cis- and trans-β-methyl-γ-octalactone extracted from oak wood (Quercus robur L., Quercus petraea Liebl.)under model wine cask conditions. Am. J. Enol. Vitic. 48:509-515.

Masson, G., E. Guichard, N. Fournier, and J.-L. Puech. 1995. Stereoisomers of β-methyl-γ-octalactone. II. Contents in the wood of French (Quercus robur and Quercus petraea) and American (Quercus alba) oaks. Am. J. Enol. Vitic. 46:424-428.

Masson, G., E. Guichard, et al. 1996. Dosage des stéréoisomèrs de la β-méthyl-γ-octalactone dans le bois des chênes européens et américains. Application aux vins élevés en fûts. In: Aline Lonvaud-Funel, Oenologie 95, 5e Symposium International d’Oenologie. Lavoisier, Londres, Paris, New-York: 451-454.

Pérez-Coello, M.S., J. Sanz, and M.D. Cabezudo. 1999. Determination of volatile compounds in hydroalcoholic extracts of French and American oak wood. Am. J. Enol. Vitic. 50:162-165.

Rodríguez-Rodríguez, P., and E. Gómez-Plaza. 2011. Effect of volume and toast level of French oak barrels (Quercus petraea L.) on Cabernet Sauvignon wine characteristics. Am. J. Enol. Vitic. 62:359-365.

Sauvageot, F., and F. Feuillat. 1999. The influence of oak wood (Quercus robur L., Q. petraea Liebl.) on the flavor of Burgundy Pinot noir. An examination of variation among individual trees. Am. J. Enol. Vitic. 50:447-455.

Towey, J.P., and A.L. Waterhouse. 1996. The extraction of volatile compounds from French and American oak barrels in Chardonnay during three successive vintages. Am. J. Enol. Vitic. 47:63-172.

Wine Folly


How to Start a Wine Label
18 March, 2019

As a custom crush winemaking facility, a common question we get asked is, “how do I start a wine label?” Because this is so common, we wanted to provide a brief overview of some of the factors involved in this process.

If you’ve ever considered starting your own wine label, it’s likely that you don’t know where to begin. Many first-time business owners might assume that you have to own your own winery to start a wine company, but that is not the case for many new labels. There are many components to consider when thinking about making your own wine, and we are here to help. If you are thinking of potentially starting your own wine label without the burden or expense of owning your own winery, here are some pertinent details to keep in mind.


Though it might sound tempting to start the process with finding grapes and immediately conceptualizing your flavor notes, it’s important to begin with considering the business side, specifically compliance. You will need the standard business items, such as Tax ID, liability insurance, etc. to get you started. From there, you should decide on whether you’ll be an alternating proprietor (AP) or not. If you decide on AP, you are required to have a bonded winery application, which will impact interstate shipping allowance (if you foresee this being a component of your wine-making business). Lastly, you will need a wholesaler permit and a 17/20 license. The Californian does a good job of summarizing the types of licenses you may want to consider further. Though many of these items probably sound intimidating, it’s important to launch from a process standpoint in order to lay out the business side of your new wine label. You’ll be glad you did.


And now, the fun part! First, you need to decide on your source of desired fruit. The grapes you choose play a huge role in how your wine may taste, so you will want to devote some time and consideration to this step. When choosing grapes, you should consider the method in which you source grapes. For example, would you like to buy grapes by the ton from a local vineyard? Maybe you’d like to buy a section of a vineyard by the row, or perhaps you can plant the grapes yourself. Keep in mind that if you do choose to plant the grapes yourself, this is a long process. You can expect three to four years to go by before you have your first harvest of usable grapes. No matter which grapes you choose, it’s important that you make a decision that you feel would benefit you and the growth of your wine label over time.

Bins of grapes arrive at the winery to be sorted and processed.


The next step in creating your own wine label will be to determine who exactly makes the wine. Winemaking is said to be both an art and a science. Because of that, much of winemaking can be attributed to a feel, and other parts can be thought of as simple science know-how. Depending on your level of comfort and experience with winemaking, you may consider making the wine yourself. However, it’s always an option to hire someone else to make the winemaking decisions for you, which could free up your time to make other important business decisions for your label.

To sort—or not to sort—your grapes is one of many winemaking decisions to be made.

Winemaking Facility

You can’t make wine without a facility. Because of that, you must decide where exactly the winemaking process will take place. Some common facilities that wine labels regularly utilize are garages, new wineries, or custom crush facilities (oftentimes called “cooperatives”).

Stainless steel tanks are frequently seen around wineries and appreciated for their versatility and ease of sanitation.

Within your decision on which type of facility to use, you should also consider what types of equipment you’ll need to purchase. One perk of using a custom crush facility is that they often have great equipment and services that are available for you to use without you having to handle the overhead and business operations of your own winery. However, if you decide you’d like to manage the facility that produces your wine, you’ll likely need to secure tanks, sorting equipment, pumps, and presses. Keep in mind that you may need to be in charge of not only purchasing these items, but also facility maintenance and cleaning. According to The Grapevine Magazine, custom crush facilities are oftentimes attractive to new business owners because of the privileges the business owners can still enjoy relative to their wine like the marketing, trademarking, and bottling of the wine. Lastly, keep in mind that different states have different laws regarding custom crush facilities, so check out your winemaking state laws before making any permanent decision on your choice of winemaking facility.


Other than the aforementioned supplies you’ll need if you decide to own the winemaking facility, there are other supplies to consider when you have your own label. You will need barrels to hold your wine while it ferments or during aging (see our blog on fermentation vessels) and glass bottles when it’s ready to be bottled. You may be able to buy wine bottles from a wholesaler, or you may want to spend time designing your own. Next, you’ll need corks to enclose the wine within the bottle (unless you decide to use twist-off screw cap closures). Lastly, you will need labels so your customers can identify your brand, and continue coming back to your wine over and over again.

Natural corks are one way to provide a closure for your wine.


Bottling is a critical moment for wine. There are a couple of options you have for bottling purposes, but the first question you should ask yourself is whether or not you are bottling your own wine. Many winemakers decide to contract out their bottling instead of bottling the product themselves. You can do this with either a stationary line at your own facility or a mobile bottling line. All methods have their pros and cons, so it’s up to you to decide what’s best for you and your wine.

Bottling is a final, critical and often stressful final step to the winemaking process.


Then comes the decision of where you will store your wine after it is bottled and before it is sold. Choosing a wine storage facility is an important step. You will oftentimes have to store the wine during bottle aging. Once the wine is ready to release, you need a reliable warehouse capable of delivering your wine where you need it to go. Another option is to store the wine at your own facility if you have space. When you decide on storage, be sure to ask about temperature control, “in and out” fees, order release procedures and insurance for your product to ensure that your wine ultimately gets to your customers in its ideal condition.

Distribution and Sales

Wine distribution and sales is a part of the wine business that can be challenging for many first-time wine label owners. The most traditional method is the 3-tier distribution process for alcohol: producers, distributors, and retailers. Another generally more profitable and time-consuming avenue is DTC (Direct to Consumer). This method has a whole host of legal challenges that can be overcome with proper compliance.

Consider your options for brokers and distributors. Who will sell your wine? How will you distribute it? Do you plan to sell your wine yourself in your own store/company, or will you contract that out to another storeroom and another shipping and logistics firm? You may want to consider having a wine tasting room in a prominent location to let potential customers taste your wine before they purchase it, or you could showcase your wine at various wine tasting events around the world. There are many distribution and sales options for wine in this growing industry, which can help influence how much wine you eventually sell.

Have Fun!

Lastly, deciding to start your own label should be a fun journey full of excitement, passion and learning! Starting a new wine business can make the “winemaking” part seem simple, and you’ll likely meet many like-minded people along the way that share your enthusiasm for wine. Here at Gravity Wine House, we definitely share the positive energy surrounding winemaking, so feel free to reach out with questions! We have experience with all of these aspects and enjoy every part of them in different ways.

Wine Production: Fermentation Vessels
07 February, 2019

When deciding what type of tank to use when making wine, you’ll likely come across a few different palatable options. Each type of tank has its own unique benefits and drawbacks, so it’s important to do your research before you set out to buy just any type of tank. Your wine is its own unique blend, so the best way to honor your wine is to ensure that its vessel helps accentuate its flavors and is a productive member of the winemaking process. In order to decide which type is right for you, we’ve summarized below the most common types of tanks, along with information regarding temperature control, oxygen levels and regulation, tannins and flavor impacts, sanitation issues, and the likely costs for each tank.

Stainless Steel Tanks

The most common of tanks, stainless steel vessels offer many benefits to the winemaking process. Not only is it fairly easy to regulate temperature in stainless steel tanks, but they are also known to be very easy to clean—and even perhaps, the easiest of all types—due to the smooth surfaces of the tanks. Sanitation is a large factor in the winemaking process, which makes this a very important factor.

Stainless steel tanks are a common sight in wineries. The properties of stainless steel make it a great fit for fermentation (and storage) tanks, and overall investment for your winery.

These types of tanks are also cost effective, so if price is any consideration (which it normally is), then this could be a big factor in your fermentation vessel decision. Additionally, stainless steel tanks are generally produced locally, so you likely won’t have to search far and wide (and pay a significant shipping fee) for this type of product. Not only are they economical, but they are also known to be a solid investment. As a metal, stainless steel generally holds its value and can be easily sold as a used vessel, as they are so common and the inter nature of stainless steel maintains it’s condition over a long time. One thing to consider as this is being written is the current economic environment and the fact that even local producers of tanks purchase steel in bulk from China, where we are experiencing higher rates.

In terms of tannin and flavor effects, this type of tank could be right for you if you don’t want to add any tannins or flavors to your already desirable wine. You can use this tank to focus and highlight the specific profiles of your fruit, knowing that the effects on the wine are due to your own winemaking decisions and not the fermentation mechanism. Lastly, the shape, taper, valve and door placement can vary by tank—essentially allowing you to produce a custom tank for you winemaking or fermentation goals. Since you will have this tank for a very long time, be sure to confirm that the vessel is the shape and taper that you’d wish before you make your purchase.

Wood Tanks

Wood tanks can be a nice addition to the winery, while also adding beneficial sensory properties to the wine.

Like stainless steel tanks, wood tanks are also very common. However, there are many components of wood tanks that make them almost a different species than stainless steel tanks (Crush Brew). For example, wood tanks add tannin to wine, which generally produces a different texture, an oak-driven flavor and aroma—a profile sought after by many, particularly for red wines. Wood also has an insulating property that keeps fermentations warmer—this can be a good thing, but close temperature control must be monitored.

Unlike stainless steel tanks, wood tanks are generally more difficult to clean and maintain. Since the surfaces of wood tanks are textured and porous, wine soaks inside of the wood. This can be detrimental, as tiny microbes can harbor within the grains of the wood, thus requiring that these vessels need constant time and attention as it pertains to the cleaning and storing process. This also goes for the color of the wine. A winemaker may consider that if your vessel is “a red wine tank once, it is always a red wine tank.” When storing wood tanks, you must both sanitize the tank and hydrate it so that it doesn’t dry out before you use it next. It’s also helpful to keep in mind, both financially and environmentally speaking, that wood tanks are used for decades, but if you are looking for the sensory impact of new wood, that will only be obtained within the first 2 to 3 years of use. Lastly, unlike stainless steel tanks, wood tanks are generally not produced locally, and the shapes of the tanks are generally cylindrical. 
Inside perspective of an oak fermentation tank. The interior of wood tanks require special care and maintenance, otherwise the porous surface of the wood can harbor unwanted microbes.

Concrete Tanks

Concrete tanks are an unconventional, older type of winemaking material that has recently made a comeback in the United States (The Press Democrat). Although winemakers in Europe have been utilizing concrete to make wine for centuries, winemakers in the US are beginning to once again appreciate the mineralistic nature of concrete tanks and the gradual flow of oxygen into the wine. A unique property of concrete tanks is their porous nature, which allows small amounts of oxygen to enter the tank and the wine during the fermentation process. In terms of temperature, concrete slowly warms and also slowly cools to create a more gradual fermentation process. Another common benefit to using concrete tanks is to get a representation of the wine itself, and not added character from oak. This would make it comparable to stainless steel, but with a different perspective. (Seattle Magazine).

Concrete tanks can be made in a variety of shapes, to accommodate various winemaking or aesthetic preferences. (photo courtesy CBC)

However, due to the concrete tanks’ porous nature, sanitation can be quite difficult. A potential drawback to concrete tanks is the challenge of the wine pigment remaining in the concrete vessel and the ability to switch back and forth from red or white wine, similar to wood tanks. (Seattle Magazine). Another common drawback to using concrete tanks is the fact that the vessel can be cracked due to the temperature of the liquid inside during fermentation or cleaning.

Like stainless steel tanks, the shape and taper can vary by tank, and because of the nature of concrete, there are many forms and varieties of concrete tanks now being produced. So it is important to think seriously about the shape and taper before making any purchase. In terms of price, concrete tanks can be on the more expensive, and harder to sell as a used vessel.


Another even older method of winemaking that has made a recent comeback is the use of amphora tanks (BK Wine Magazine). Throughout history, amphora tanks were made out of clay and buried in the ground during wine fermentation to protect the wine from oxidation. It is worth noting that while this was a way to protect wines from oxygen, if that is the main goal, there are other ways today for better oxygen protection (stainless steel, for example). They are regularly hailed as one of the most ancient and natural methods of winemaking. These tanks are made in a variety of different sizes.

A trio of amphorae. In ancient times a clay amphora was commonly used to ferment and store wine. Often times the amphora would be buried in the ground for support or temperature control. (photo courtesy Australian and New Zealand Winemakers)

A drawback to using amphora tanks is the intensive labor required to produce wine this way, the limited ability to include doors and valves, and also the challenge of staving off oxidation (while this was a great method of of preventing oxidation in the past, there are now other more secure methods).This method may limit the amount of wine you’re able to produce and labor fees may be high. Furthermore, generally there is a very small market for these types of tanks in today’s modern world, but it is always helpful to see where we’ve been before you decide where you may want to go.

In conclusion, there are great options of fermentation vessels to choose from when producing wine, but depending on the various components of each type of vessel, there will be one that best suits you and your wine. To ultimately choose what type of tank you’ll trust your wine to ferment within, it could be helpful to make a list of priorities for both production and wine taste and then find your best vessel from there, and even to make a sketch of the tank and accessories you would like before contacting your supplier.

Mark Your Calendars for the WIN Expo
16 November, 2018

Mark your calendars! Gravity Wine House will be attending the WIN Expo in Santa Rosa on Thursday, December 6th.

We invite you to swing by booth #506 for all of your custom crush needs and are looking forward to seeing you there!

Gravity Wine House will attend the WIN Expo in Santa Rosa.

Title Name Email Phone
General Manager Jacob Quint 541-282-3466
Production Coordinator Lindsey Svendsen 707-545-6670