We have talked about acidity a bit on this blog, from how to measure acidity and how it is different from pH to comparing the acidity of Coca-Cola and vinegar. Vinegar obviously comes in different acidities though. Which one do you need? How do they help? Below is a quick and informative guide to vinegar acidities and their usages.
Acidity is defined as grams of acetic acid per 100 mL water
<4% acidity This is not legal vinegar to be bought and sold, though what you use at home is your business. Never buy any vinegar (defined as vinegar) less than 4% acidity. Only vinegar in fermentation should be this weak. Kombucha and other fermented foods don’t apply since they are not vinegar and are not defined the same way.
4% acidity This is the minimum legal acidity level for vinegar in almost all countries. Most bargain and discount vinegar brands now are 4%. They don’t advertise this in large print so check the label. Only use for basic cooking and salad dressings. Do not use for canning. Vinegar this weak is less effective at cleaning as well.
5% acidity The standard acidity range for most vinegars. Good for use in canning if you are using good canning practices. Also can be used for any variety of cooking and most types of cleaning. Too weak to use for weed killer except in large amounts.
6-7% acidity Most wine and balsamic vinegars fall in this range. Balsamic vinegar of Modena is at least 6%. Can be used in any way from cooking to canning. Likely too expensive for cleaning. This is the typical upper range for food vinegar.
10% This is a high strength vinegar. Be careful consuming it as it is very acidic and can cause burns. Also wear gloves (latex or nitrile, not cloth) when handling since it can irritate your skin (especially cuts) and cause eye burning. This is the typical acidity of vinegar made in factories. It is superior at cleaning and is the lowest acidity for effective weed control though it will require more amounts than equivalent chemicals. Some Eastern European or Scandinavian countries sell this for cleaning or fish pickling.
For all vinegars over 10%, the instructions below are recommendations. You must read the Material Safety Data Sheet (MSDS) for high strength vinegars before using.
15% The mid-level of high strength vinegar. Only used in cooking in amounts of 1/3 typical vinegar and usually used for cleaning and weed killing. Gloves and eye protection should be used when handling. Rinse of any skin contact immediately.
20-25% This is rarely sold to the public except as weed killer. It is made by centrifugation of lower acidity frozen vinegar crystals since vinegar bacteria can’t make vinegar this strong. Germany’s Surig sells Essigessenz which is 25% acidity and can be used for cooking in only very small amounts. Gloves and eye protection are required in even small amounts. Gloves should be latex or nitrile and eye protection should be chemistry lab type goggles, not plastic impact safety glasses. An apron and arm covering as well as a respirator should be used for handling large amounts. Only open or pour these vinegars in areas with good ventilation. Rinse any skin contact immediately and do not touch eyes or nose without thoroughly washing up. If using as weed killer, do not spray into the wind and do not spray anything metal you don’t want possibly corroding.
30% This is the upper limit industrial vinegar sold. Also made by centrifugation it has almost no other use for the general public except as weed killer. If using this as weed killer, ABSOLUTELY use hand and eye protection (chemistry goggles, not loose plastic safety glasses). No substitutes for latex or nitrile. Nylon can be corroded. Depending on your sensitivity, even a small spray mist can cause lung irritation so use at least a face mask if not a small respirator. Only spray or use this outside with plenty of fresh air. DO NOT spray into the wind, preferably use when there is no wind present. Do not spray metals or limestone as they will rust and corrode rather quickly.
If handling in larger quantities where there can be spills, a full protection suit (e.g. Tychem QC) like below and a respirator are required.