What Does Alum Do For Pickles?

Ever heard somewhere that putting alum in jars containing pickles is heavily beneficial?

It’s true actually, alum does provide benefit when used in pickling. But what is this purpose that it serves, and is alum even safe to begin with?

This articles explains what alum does to pickles, why it is no longer recommended to be used in pickling, what the alternatives are for alum in pickling and how you can use these alternatives to achieve the purpose that alum itself serves.

What is an alum?

Alum is a chemical compound that is commonly used to purify water and also in dyeing.

Alum also has the added advantage that it could be used as a firming agent for vegetables prone to softening during fermentation, although such powers of alum is essentially missing in quick process pickling that involves submerging vegetables in a solution of water, vinegar, salt and possibly sugar for a short period of time.

In essence, alum is considered to be only useful in fermented pickles and should not be used in quick process pickles because it wont make them crisp up.

One of the popular brands that offer food grade alum to be used for pickling is McCormick Alum. 

Why is alum added to pickles?

The main reason why alum is added to pickles is to affect texture, in other words, to give the pickles a crunchy texture.

Alum has been used for this purpose for ages, but is now being phased out for a much better alternative which is calcium chloride.

We’ll discuss why the phase out is happening in a moment.

Does alum change the taste of pickles?

While alum is pretty good at what it does which is to crisp up vegetables in pickling, it does have the potential to change the taste of the pickles to a bitter or astringent one when used in excess, which is one of the main reasons why it is being phased out and not recommended to be used for pickles.

Why is alum no longer recommended for pickling?

Aside from the fact that alum can give a bitter taste to food items, it also has the potential to cause digestive upset in some individuals. These two reasons mentioned are the reasons why alum is no longer recommended for crisping up vegetables like cucumbers.

What are the best alternatives for alum?

Calcium Chloride

Calcium Chloride or “pickle crisp” as it is colloquially called is the best way to achieve a crisp pickle without the dangerous side effects of alum or any other dangerous side effect for that matter.

Calcium Chloride can be identified by its white crystalline granules at room temperature which can be shaped differently depending on the brand making it.

Calcium Chloride is great for crisping up vegetables that soften during fermentation, but it in no way will restore crispness to an already softened vegetable. Those are completely not fixable and simply have no option but to deal with them as they are.

To use pickle crisp in your pickles, add the specified quantity (as per the manufacturer’s instructions) into the jar containing the vegetable and brine, then incorporate it into the mixture using a wooden spatula and then proceed to adjust the lids and process the jars using the water bath method or a pressure canner.

Removing the blossom end of the cucumber

It is a well-known fact that the blossom end of the cucumber contains enzymes that promote softening of the vegetable. You need to remove these ends to ensure a product that stays crisp during pickling.

So, always identify the blossom end of the cucumber and cut out 1/16” from it prior to stuffing the cucumbers into the jar.

It might sometimes be very tricky for one to differentiate between the blossom end of the cucumber and the stem, especially when you’re dealing with a store bought cucumber (as cucumbers harvested from gardens have their blossom ends opposite to the stems which you can clearly point out when harvesting).

For store bought cucumbers, the blossom ends would be the end with the rough dot as opposed to a smooth indented dot. If you’re still having trouble differentiating which end has a smooth dot and which end has a rough dot, just trim off both ends and you’d still be good to go.

Using pickling cucumber as opposed to regular cucumbers

Cucumbers come in many different varieties and you want to make sure you’re sticking with the variety meant for pickling if at all you want to end up with a crispy, nice result as well as pickles that taste good.

If you use the slicing cucumber variety which is meant for cooking or slicing into salads, the cucumbers are likely to turn soft due to the wider seed base present in them in comparison to the pickling cucumber.

The burpless cucumbers are those that typically do not have seeds in them, but they have much tougher skins which would make eating them as pickles not enjoyable.

They also also contain enzymes that can cause softening during fermentation.

When it comes to choosing the right kind of cucumbers for pickling, always go for the pickling variety which are normally labeled with names like gherkins, cornichons and kirby.

These cucumbers are much smaller than regular cucumbers and have a bumpy skin.

Use really fresh cucumbers

Starting out with a pickling cucumber is not usually enough to obtain a crisp cucumber in the end after pickling.

To really have a chance at a crisp cucumber, you have to start with cucumbers that are really fresh and free from any bruise or any prior infestation. This would provide the best taste, texture and would also make sure your pickles don’t end up rotting in the fermentation brine.

So it’s always advised to use garden cucumbers at least 6- 12 hours after harvesting them as they immediately begin to undergo changes inside that would cause them to deteriorate in quality. 

For store bought cucumbers, still apply the same rule, which means you should not leave them out for more than 12 without purposing them into pickles, if that was the initial goal.

Also make sure to wash the ends of the cucumbers thoroughly using a vegetable brush so as to get rid of trapped dirt that can harbor bacteria and speed up spoilage.

Soak really fresh cucumbers in iced water for 7 hours prior to pickling (or use the refrigerator)

One method popularly used to crisp up cucumbers for pickling involves soaking them in iced water for 7 hours. Using an iced water isn’t a must, as you can simply pop the cucumbers into the refrigerator instead.

You have to be aware however, that the quality of cucumbers you begin with would greatly determine the effectiveness of this method.

Fresh and strong cucumbers would produce crisp results, whereas soft and old cucumbers would not crisp up, no matter how long you soak them in iced water.

Use water with calcium in it

Earlier we made mention of using calcium chloride as a firming agent in pickling.

You can also use water that has enough calcium in it for this purpose. Mind you that the result might not be as satisfactory as when calcium chloride is used.

To use water with enough calcium in it, soak the cucumbers in it overnight and then continue to prepare the rest of the brine using the same calcium water.

A quick note! 

Never use frozen cucumbers for pickling

I don’t know who needs to hear this, but I hope there’s no one.

You should never use frozen cucumbers for pickling for the same reason why you should never use old or limp cucumbers for pickling, it will turn out soft, mushy and will certainly not be enjoyable to say the least.

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