What water should you use when making a wine kit?  Is bottled mineral water best for making a wine kit? or is tap water the best for making a wine kit?

You may think using tap water or bottled mineral water is best when making a wine kit a home, but there are large differences in dissolved minerals in water from different sources.

Let us explain how to get the best water to use when making a wine kit and why it matters.

Most wine kits have had the grape juice concentrated, so you need to add water to the concentrate.  The manufacturers of the kits have already made some changes to the kits to account for you needing to add water back in, but we have such a wide range of mineral levels in our tap water here in the UK, the kits can't cover all eventualities, so we need to make a few adjustments when making the wine kits to get the best wine possible.

The grape vines have filtered the water when the grapes were growing and have used the minerals in the ground water to make the grapes juicy, fruity and flavoursome.

When the grapes are pressed, all that lovely grape juice is extracted.  When it is concentrated, only the excess water is removed.  This makes it a lot easier and more cost effective to transport.

But depending what water you use to rehydrate the concentrated grape juice back to its non concentrated level can have a huge effect on the finished wine.

In the concentrated grape juice are compounds and acids.  These can react with the compounds, alkalis and acids in the water you are going to add to the wine kit.  This can cause your finished wine to be very different to that which you would expect from that grape variety.

Using hard water, that's water with a lot of dissolved calcium carbonate (lime) can react with the acids in the grape juice and neutralise them.  This will result in a smooth wine, with very little acidity and this can make the wine seem lack lustre, and feel like its missing something.  It can make the finished wine seem less fruity, seem less zingy and less refreshing.

You'll know if you live in a hard water area by looking in your kettle.  When you boil your kettle, minerals dissolved in the water stick to the element and cause a yellow/white/grey fur to start building up.  This is the calcium.  

If you have ever descaled your kettle, you'll buy a descaler from the hardware store and if you read the ingredients, you'll usually find it's citric acid.  When you put that in your kettle, it fizzes as the acid and calcium carbonate react with each other.  They create CO2 and water.  The calcium carbonate disappears and the acid looses its acidity and basically turns to water.

What does that have to do with the wine.  Well the acids in the grape juice concentrate react with the calcium carbonate in the water and the hard water becomes soft, but more importantly the acids loose their acidity and turn to water.

Now if you live in a soft water area, you are so lucky. Lush water that lets shampoo bubble up into a luxurious velvet lather. No scale in your kettle, and more importantly, water that's great for making wine kits.  Soft water does not have the high levels of minerals in it, meaning there is no calcium to react with the acids in the grape juice.  This means it's great for making wine kits!

For the rest of us that live in a hard water area, there are a couple of options.  We can add more acids, or we can adjust the mineral profile of the water.

So lets look at the 3 main options...

Knowing the hardness of your water

Knowing how much calcium in your water is a good place to start.  You can contact your local water company and they can give you the details of the minerals in your water.  Or you can buy a water hardness tester kit. These are relatively cheap and you can use them over and over again as sometimes the source of water in your pipes can be different. It may come from a different reservoir, or a river, or an underground aquafer depending on the time of year, weather conditions, etc, etc.

If you know the harness of your water, then you can adjust your water before you add it to your wine kit.  Only adjust the water you are adding to the kit before you add the water.

Adjusting your Water with Acid

Hard water can easily have and alkalinity of 300mg/litre of calcium carbonate dissolved in the water.  To reduce this down to a suitable level of around 50 mg/litre will mean adding acid -

Adding acid to a wine kit

Using Acid Blend.  Knowing how much acid blend to add is science, and will depend on the hardness of your water, the amount of acid in the grape juice concentrate differs per kit and how much water you are adding.

Acid Blend should be a mixture of Tartaric, Malic and Citric acids. The ideal ratio would be 80% Tartaric acid, 19% malic acid, 1% citric acid by weight.

So, you'll need an acid test kit.  Once you have added your water to your wine kit, put on the lid of the fermenter and leave for up to an hour for the acids and carbonates to react with each other.  Then use the acid test kit to work out the pH of your juice. 

Ideally, red wines should be around 3.4 - 3.7pH. White wines should be around 3.2 - 3.5pH.

To increase acidity by 0.1pH, add 0.5 gram of acid blend per 1 litre of juice.  So for a 23 litre batch, adding 11.5grams will increase the whole batch by 0.1pH.

Be cautious adding acids, always up the pH by 0.1pH point at a time and retest the pH until you reach the desired level.

You may have to make a few brews to get to the desired finished acidity level, so make notes of how much you used and your pH readings.

The wine kit manufacturers have already adjusted the wine kits for the correct acidity levels if you are rehydrating the kit with pure water with no minerals.  So if you can get pure water, then use this.

Using AMS

0.35ml of AMS will reduce 1 litre of water by 64mg of alkalinity.  So you will now need to calculate the amount of AMS needed.  

First work out the harness of your water.  Then minus 50. Divide this by 64. Times this by 0.35.  This is how many ml of AMS you need to add to each litre of water.

For example.  Our water is 300mg Alkalinity. Minus 50 = 250mg.  250/64 = 3.9.  3.9 x 0.35 = 1.36ml AMS per litre of water.

Then times this number by the amount of extra water needed for your kit.

If your grape concentrate is 10 litres, you'll need to add 13 litres of water.  Times the amount of AMS per litre by the amount of extra water.

So in our example, we need to add just 13.5ml of AMS to our 13 litres of really hard water to get it to the right pH level to add to the wine kit.

AMS is very strong acid and is very dangerous, so skin protection and eye protection must be worn.

AMS will also increase the sulphite & chlorite levels, so just be aware of this. Though even with our hard water here with an alkalinity of 400mg, the amount of AMS needed doesn’t cause the levels to exceed allowable levels.  

Filtering the Water

If you have a water filter at home, then this is a fantastic option to filter your water to remove chlorine and unwanted minerals and micro plastics.  However, they do not remove carbonates, so if you are in a hard water area, this is not an option.  The filters use an ion exchange to change calcium carbonate to sodium carbonate. This is in effect softening the water by changing one carbonate type to another.  Sadly the carbonates are still there so will react with the acids in the wine kit and is the same as using hard water.

If you live in a soft water area, then home filters like Britta water filters are a great idea.  They slowly filter the water, so it will take you a long time to filter all the water you need for a wine kit.  Though you could set up a bucket above the other, the top bucket with a tap, sit the filter below the tap and drip feed it overnight and by the next morning you will have all the filtered water you need for your wine kit.

Chlorine and Chloramine

In the wine kits (from the pressed grapes) there are sulphites.  These help protect the grapes and grape juice from infection and also help prevent the grape juice oxidising.  What do sulphites have to do with chlorine, well, chlorine and sulphites react and they create a salt - table salt. So little salt that it is imperceptible, but it means that the sulphites are reduced and the chlorine is neutralised.

However, both chlorine and chloramine will have an effect on the yeast, slowing them down and preventing multiplication.

If you are using tap water, go back to the report you have from your water supplier.  It should tell you if they are using chlorine or chloramine to disinfect the water.

If it's chlorine, great.  There is an easy way to get rid of chlorine from your tap water. Just draw off the water 24 hours before you want to use it. The chlorine will evaporate and dissipate, leaving chlorine free water. 

However chloramine doesn't evaporate, so if your water supplier uses chloramine, it's probably better that you use a bottled water.

Bottled Water

The good thing about bottled water is the mineral content is printed on the label.  Very helpful if you are looking for a water with a low mineral content.  Carbonates should be as low as possible. Calcium should be as low as possible. Using a bottled water with high calcium or high carbonates is basically the same as using hard water. 

Distilled Water / Reverse Osmosis Water

This is water that has been purified and had all minerals removed. In distilled water it has been evaporated and condensed leaving all the impurities in the evaporator.  Reverse Osmosis (RO) water has been filtered to remove all the impurities.

The World Health Organisation does not recommend drinking Distilled or RO water for regular consumption over a long period as there are no minerals, but provided you have a healthy diet and have the missing minerals from other food sources there shouldn't be a problem.

Both Reverse Osmosis Water and Distilled water are great for making wine kits that have at least 7.5 litres of concentrated grape juice. Below 7.5 litres of concentrate, it lacks the minerals that yeast need for a healthy fermentation, so you may find you need to add minerals back to the water.

Above 6 litres of concentrated grape juice, all the minerals, flavours, sugars etc that are needed for a healthy fermentation to make the wine. In theory, the manufacturers of the wine kits have only removed the water from the grape juice concentrating it, so using Distilled or RO water is the best option.

A downside is that Distilled and RO water for human consumption is quite expensive. A 25 litre container of RO / distilled water is currently (Oct 2026) £25 + delivery. 

You can buy a reverse osmosis filter and filter your water at home.  These can be plumbed into your mains water supply and you can have a filtered water tap by your sink.  These are great (although a little expensive) and they mean you get pure water as they trap everything. 

In Summary

• If you are using tap water, pull it off 24 hours before you are going to use it to allow the chlorine to evaporate.
• If you live in a soft water area, then use the tap water.
• If you live in a hard water area, and you are using tap water, you will need to add acids to neutralise the carbonates dissolved in the water.
• If you live in a hard water area, then look at using distilled or reverse osmosis water option as this is probably the best water to get a wine as if they had never removed the water from the grape juice in the first place.
• For kits with less than 7.5 litres of concentrated grape juice, if you live in a hard water area, then use bottled water, or tap water and adjust the carbonates using acids.
• For kits with more than 7.5 litres of concentrated grape juice then if the budget allows, or if you have a reverse osmosis filter, then use either distilled water or RO water.

 

Hopefully, from our short article, you should now be able to adjust your water to help you make an amazing tasting wine.  As always, if you need any help with this subject, then just get in touch.

Cheers and happy brewing.

Davin