BerryTestAction: Holds descriptions of how we test berries during their final weeks of maturation so we can decide when to harvest.My approach: I go with about 1/2 tsp of 10% solution per gallon of cider.This page describes the tables used primarily to capture data in Winery activities. Commercial winemakers add sulfites at various stages (including when racking) to reduce oxygen pickup I don’t know any home cider makers who do this. You shouldn’t be hitting this as a home cidermaker, but if you use sulfites up front (e.g., Campden tablets) to control wild yeasts and microbes, do the math to be sure. The US legal limit for sulfites in cider is 300 mg/L, counting all additions. (The above-linked article “Solving the Sulfite Puzzle”, with instructions for mixing and using a 10% solution, leaves this out of their example calculation, which confused me for a while.) Using a calculator like the one linked above will include this adjustment when recommending a volume of 10% solution, but if you’re working out your own numbers you’ll want to keep this adjustment in mind. When the potassium metabisulfite molecule, K 2S 2O 5, dissolves in water, it gives off two molecules of SO2, comprising 57.6% of the original molecule’s weight. Note that a solution of 10% potassium metabisulfite is functionally a 5.76% solution of SO2.
A 10% solution is the easiest way to add sulfites, as the math is simpler and you don’t have to worry about dissolving your sulfites each time. To achieve this, the calculator suggests adding about 2.6 mL of 10% sulfite solution per gallon of cider – which is just slightly more than 1/2 tsp per gallon.
When I punch in BYO’s recommended goal of 30 mg/L of free SO 2, the calculator suggests I target 36-42 mg/L instead, based on pH. Try Winemaker Mag’s sulfite calculator, treating your cider as a white wine – you can enter the actual pH and ABV, so this doesn’t seem like a misapplication. If you haven’t yet added sulfites, let’s assume you have no free SO 2 in your cider.īYO recommends a sulfite addition of 30 mg/L. Professionals have procedures for estimating free SO 2, as they add sulfites at various stages to maintain a desired SO 2 level. Sulfites are discussed in terms of ppm of sulfur dioxide (SO 2), as this is what matters and there are several ways to add sulfur dioxide to wine or cider. More complicated process, but more coherent estimates. My approach: just go with the recommendation on the label: 1/2 tsp per gallon, aiming for 0.3 g/L – the limit allowed in American winemaking. Unfortunately for us, cider is generally much less alcoholic than wine ( pH is similar ... I think?). This winemaking guide, quoting Peynaud (1984), notes that sorbate is more effective – and thus less is needed – at lower pH and higher alcohol %. This is much higher than all other recommendations, with no justification provided. Thus the container recommendation translates to 0.29 g/L.īYO recommends a sorbate dosage rate of “0.5 to 1.0 g/L”. The container from the homebrew store says “1/2 tsp per gallon.” My high-resolution scale says a typical 1/2 teaspoon of sorbate weighs 1.1g ( this container has been opened many times, and perhaps has absorbed moisture). There are legal limits of 0.2 g/L (Europe) and 0.3 g/L (America) the sensory level for perceiving this chemical’s flavor is reported at 0.135 g/L.Īdjusting these from sorbic acid -> potassium sorbate (what a homebrewer weighs) gives legal limits of 0.26 g/L and 0.4 g/L, respectively, with a taste threshold of 0.18 g/L. Winemakers talk more about sorbic acid, the relevant chemical potassium sorbate is 74% sorbic acid.
Longer version How much potassium sorbate? Tl drįor each gallon of cider, use 1/2 tsp of potassium sorbate and 1/2 tsp of 10% sulfite solution (an extra step, but worth making – the solution is easier to work with than dry potassium metabisulfite). This guidance from BYO magazine on backsweetening provides background on the approach. The most common method in home cidermaking is to add both potassium sorbate and potassium metabisulfite (“K-Meta”). If you add sugar to hard cider and don’t want that addition to restart fermentation (which would increase alcohol and leave the cider even drier), you’ll need to stabilize it. I re-researched this every fall when it came time to backsweeten the previous year’s cider, so I wrote this guide to future me.