How to Choose a Stainless Wine Tank!
The use of stainless steel tanks in home winemaking is fairly common. Because winemakers only get one chance each year to begin the winemaking process (when working with fresh grapes) and because the amount of work that goes in to making 50 gallons of wine is not much more than goes into making 5 gallons of wine, especially when you can store the wine in a single container. Since nobody wants to deal with 10 carboys laying around, stainless steel tanks or oak barrels become the main vessels that wine is stored in for aging. Stainless is often preferred because it is easier to maintain, and can be used for both fermentation and aging. There are two basic styles of tanks: Variable Volume Tanks (also called Variable Capacity or Floating Lid Tanks) and Sealed Tanks.
Variable Volume tanks are so called because the lid for the tank can be set at any level by inflating an inner tube-like bladder that is stretched around the rim of the lid. This means that the winemaker can have pretty much any volume of liquid in the tank and still have it effectively filled completely. Since preventing oxygen contact is so important when aging wine, this is a huge advantage for home winemakers whose lots sizes may vary from year to year. The disadvantage of these tanks is that the clear vinyl lid bladders that are typically included with them can have trouble forming a good seal, which can lead to oxidative damage to the wine. This is the major reason that a winemaker would not work with a Variable Volume tank, and is not an issue with our tanks because of the upgraded White Rubber gaskets that we include with our tanks.
Sealed Tanks are also sometimes called Fixed Volume tanks because they do not feature the Variable Volume lid. The tank has to be filled completely, or flushed out with inert gas, in order for the wine inside to stay protected from oxygen. Some winemakers will elect to work with these tanks because either they or someone they know has had a bad experience with the Variable Volume tanks. Of course the main drawback to Sealed tanks is that you have to have either enough wine to fill the tank or an inert gas system to use for flushing it out.
There are also two basic configurations of these tanks, either Flat Bottom or Conical Bottom. Flat bottom tanks are just what they sound like, tanks with a flat bottom. These tanks are less expensive, but you cannot rack all of the liquid out of the valve at the bottom (think about the valve placement on a brewing kettle - same deal). Conical bottom tanks are built on legs and have two ports at the base of the tank, one for racking and one for total drainage. Typically a winemaker will rack out of the higher port (appropriately called a Racking Port) and then drain all the lees and other sediment out of the bottom port (called the Drainage Port). Both Variable Volume and Sealed tanks are available with either Flat Bottom or Conical Bottom configurations. Flat bottom tanks max out at about 1000L (250 gal) capacity, because any larger than that and you would be an idiot not to work with a conical bottom tank.
When it comes to helping a customer size a tank, it is important to know if the tank is going to be used for Fermentation, Storage or Both. There's nothing fancy or special to keep in mind if the tank is going to be used for storage alone - the appropriate size of tank for the customer is going to correspond to how much wine they want to store. If the tank is going to be used for fermentation you have to keep two things in mind: 1) you want to maintain about 25% free space in the tank for foaming (white wines) or cap development (reds) during theferment; and 2) red must is about 30%-35% solids. So, to yield 50 gal of wine you will have 65-70 gal of must and therefore need a tank capacity of about 95 gal in order to keep your 25% free space for the cap.
Standard Configurations of our Tanks
Depending on which tank you're looking at, the standard features for that tank will vary. For the most part the tanks come as bare cylinders of stainless steel without any modifications, except for the ability to connect a valve(s) to it. Let's run through the different configurations: GER100VF(PREBOOK) & GER220VF(PREBOOK): These are our main small tanks for home winemakers, and the only tanks that we sell which actually include valves as part of the purchase price. These two models of tank come with two 1/2" FPT ports, one for the ball valve and the other located about 6" above the valve to accommodate a thermometer. The tank does not include the thermometer, but will come with a stainless plug for that port so that the customer does not have to purchase a thermometer to make the tank work.
GER300VSTOCK & GER650VFSTOCK: These are the only other two sizes of tanks that we bring over to have in stock at wine season. These tanks are configured at the factory so that they can accept either a Sample Valve or a Thermometer. The PreSeason version of these tanks do not automatically include the port necessary for this. You will use the same SKU for the sample valve or thermometer that goes with this tank as though the customer had ordered it during the PreSale.
All Other GER Tanks Up To 1600L Capacity: All other Speidel tanks up to 1600L come with no additional features besides the appropriate number of TC valve ferrules (1 for Flat Bottom tanks, 2 for Conical Bottom tanks). Tanks in this size range are set up to work with 1.5" TC fittings.
All Other Tanks 1600L And Larger: These tanks are the same as the last category, except that we set them up to work with 2" TC Valves.
Tank Options and Why You Want Them
Any tank that is ordered during the PreSale can have a variety of different optional features added on to it. The range, scope and cost of the options varies from tank to tank, so let the website be your guide when determining what is available for a given size of tank - all of the available options are listed in the "You Might Also Need" section for each tank.
Options for both Variable and Sealed Tanks
Sample Valve: Just what it sounds like, a small valve installed on the side of the tank that allows the winemaker to draw off small samples for tasting or lab work. More efficient and cleaner than trying to do this with the regular racking valve.
Thermometer / Thermowell: Unlike other companies, we offer these two items together as part of the same option. A thermowell is a stainless steel well that you can put the probe from a digital temp controller into in order to monitor the temperature inside the tank. Our system works such that you always have the thermowell installed, but in case you don't want/need a digital controller a conventional analog thermometer is included that you can install in the thermowell in lieu of the probe from a digital controller.
Cooling Jacket: A cooling jacket is basically like an extra exterior wall for the tank that allows cold water/glycol to be passed through the space between the jacket and the regular tank wall in order to change the temperature of the wine in the tank. On smaller tanks this can be achieved with cooling plates or snakes, but after about 1000L in size the tank has to be jacketed in order to do heating/cooling of the wine inside it. We offer two sizes of cooling jacket: a more basic one that we call a "Cooling Band," and then a more substantial one that is the most that Speidel can install called a "Maximum Coverage Jacket." Typically the Cooling Band is more than sufficient, but some winemakers want as much of the tank covered as possible...
Levelling Feet: Many wineries have sloped floors in order to facilitate draining the water / wine / etc that inevitably winds up on the floor. Levelling feet help to keep tanks perfectly upright even when they're on sloped floors. The feet thread in and out of the main tank leg, making each leg adjustable.
Pumpover System: As we all know, during red wine fermentation the solids from the grapes will be pushed to the top of the tank and form a "cap." This cap can be very thick and can trap a large amount of pressure underneath. In tanks larger than about 1000L this cap becomes so thick and pressurized that it can be impossible to punch it down by hand. Pumpover systems allow the winemaker to draw liquid from the bottom of the tank and pump it back over the top of the cap. This wets down the cap and will either break it up on its own or at the very least it will weaken it to the point where it is possible to punch down manually.
Sight Gauge: Also called a Sight Glass, a Sight Gauge is basically a narrow tube mounted vertically on the side of the tank that you can allow wine from the tank to flow into. The tube will only fill up to the height of the liquid inside the tank. This is used for determining how full a tank is for tax purposes, or for helping to determine percentages when blending. Though a relatively inexpensive add-on, we usually only recommend having one tank equipped with one as they are pretty tough to keep clean.
Fermentation Manway: A fermentation manway is a special upgraded manway that includes a beefy sloped channel being installed into the base of the tank. This is designed to help with the evacuation of red wine solids after fermentation. The manway opens along the top edge rather than the side edge as well.
Options For Variable Volume Tanks Only
Manway Upgrade for Variable Tanks: The standard configuration of a Variable Volume tank does not include any manway at all. This option installs a standard manway at the base of the tank. Manways are very helpful for cleaning & sanitizing tanks.
Options For Sealed Tanks Only
Top Hatch for Sealed Tanks: This option installs a round hatch in the top of a sealed tank that allows access for cleaning or punching down. We have two different hatches available: either centered in the top of the tank or set forward so that they're easier to reach when leaning a ladder against the tank.
Manway Upgrade for Sealed Tanks: Sealed tanks come standard from Speidel with an oval manway installed in the side wall of the tank that is designed to give access for cleaning / sanitizing. This oval manway is not located right at the bottom of the tank, so it is not suitable for removing solids after red fermentation. The Manway Upgrade substitutes a rectangular manway at the base of the tank for the oval one that would have been there.
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