Acid.... The what does it do series

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Oct 31, 2006
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Following on from what campden does, what is the purpose of adding acid?

I tried something 'strange' at the weekend, being forced to go to the god awful place that is Ikea I looked arounf the foody bit at the end and descovered an elderflower syrup concentrate and noticed it contained no preservatives so the experiment was born.

I made up the concentrate as directed, added yeast nutrient and sugar using my hydrometer to judge.

I noticed that the concentrate had citric acid as an ingredient so was unsure how much (if any) to add? I decided to add half the recommended amount for a gallon as the juice already had some in.

I skipped campden assuming the juice would have been made a sterile environment and pitched my yeast.....

...well its definately fermenting although somewhat slower than I would expect given the sugar levels, and when I stir it it almost stops. Any ideas why so slow? I was wondering if it was an acid issue?

It only made 3.5l so I will need to top it up with a litre of something and am undecided between using more of the elderflower concentrate or adding some apple juice/sugar/nutrient/acid?

Any help/views apprecieted - Rob
Hey Bob, In the first place I presume that there will be no nutrients in the must so I would advise to add them as soon as possible. Without them the yeast will not survive.

Second get yourself an acid titration kit so you can test the acidity of the must. Acid has several points of interest in a wine.
a) most wines have an acidity between 5grams and 9grams per liter that is according to the type of wine. Port has 4 to 5, whites 6 to 7 and reds anything goes as long as it tastes well and suits the type of wine. A wine without acidity tastes awfull and sometimes like medicine because you will taste the alcohol.....
b) Acidity helps in preserving the wine.
c) A wine to low in acidity slows down the fermentation

So get yourself an acidity titration kit and start testing the must, and acid to a desired level. Luc
As luc mentioned wines need acidity. The two main reasons are for taste balance and also that yeast needs a slightly acidic environment (with nutrients) to function fully.
The concentrate you used contained some acid and adding a little more certainly won't have hurt. Get some nutrient in as soon as you can - adding extra water/sugar is down to your own alcohol requirements dependent on your initial readings. I tend to start with a 'must' that's 10% larger than I need in primary and then rack it after a few days to a glass demi-john or carboy to avoid topping up.
Thanx, as mentioned in my original post I had already added nutrient.

Its fermenting very well at the moment its just difficult to see as the liquid/must is white. I have no idea how good or bad this will taste it only cost £1 for the concentrate and was purely a lets see for fun of it kind of thing.

The acid test kit sounds like a good idea I will get one at the weekend, thanx again

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Thanx, as mentioned in my original post I had already added nutrient.

Oops I missed that also.

Elderflower Syrup is just great. I make it myself each year just as I make Rose Syrup.
Both are also well used for sweetening and flavoring wine, but are also great for making icecream :)
Not sure how much this note from Jack Kellers site will help you.


Calcium Carbonate (precipitated chalk) (treatment):
Used to reduce the acidity of wine or must. Because it reacts preferentially with tartaric acid over malic acid, separate out a small portion of the batch, treat it and then recombine the portions. Since pH increases concurrently a drop in acidity of more than 0.3 to 0.4% is seldom practical. Use calcium carbonate as early as possible to allow sufficient time for tartrate stability and the reduction in taste from calcium ions. 2.5 grams/gallon will reduce acidity by about 0.1%.