How real Slivovitz - or Slivovice is fermented:

How to ferment plums to make Slivovitz or Slivovice

Plum Fermentation




The plum fermentation container

Yep, that really is a plastic container usually used for chemical waste or other undesired materials.

Obviously this one started off as new and no toxic materials ever came in contact with it and from the start this plastic barrel has always been used to ferment plums for Slivovitz making.

This is a standard plastic waste container available throughout the world and it can contain up to 120 Litres of liquid.


... the actual container was out in Luda's back garden through from the start - being from September onwards, and the summer temperature only helped the plums to get on therir way to fermantation.


Plums in a fermenting barrel

When Luda started harvesting the plums around the end of July 2005, all he would do is just pile them into the plum fermenting container and close the lid.

The contained was topped up each time mmore new plums had been harvested and this went on till about mid September when all the plums had been collected and placed into this ccontainer.

Each time new plums were added nothing was stirred or shaken but the container was covered with it's lid...





Plums fermenting

This is about three weeks later after the last plum harvesting mid September

and you can notice that the plums have started to change colour and the actual fruit structure has changed from a nice eatable plum to fermented fruit.
Which is good as it means the plums are fermenting.


Adding latest harvested plums into the fermenting brew

Plums are added into the fermenting brew as they are picked at the 8 or 10 intervals during end of summer and here you can see that the last bucketfull has just been added...




Mixing the fermenting plums

... and at this time since most of the brew has already been fermenting for about 1 month since the beginning, the whole brew needs to be mixed and for that we have a special plum mixer.



The plum chopper/mixer

And here is the plum mixer.

Yes, that really is a standard boring drill but insted of a drill head it has a long rod of metal attached to it. like a mixer's blade

This rod has an ending pice which has been soldered to it so as to make a T shape The end is actually sharpened on both sides just like a knife , making this a perfect mixer for the heavy plum brew




The plum mixer in action

Almost like making whipped cream.

As you see the rod is long enough to reach to the bottom of our fermenting container and all one needst to do is stick the plum mixer inside the brew and turn on the drill.



This helps the fermentation process to arrive at it's final stages quicker and mainly opens up any not so soft plums up to now so that they too can be exposed to the fermenting faries.


Mixing the plum fermentation

The point of this mixing the plums is that up till now the plums have been left in their wholeness.

Obviously the fermentation process breaks the plums up quite a bit as they sort of start to fermentovat but up to this point most of the plums have continued to be attached or to contain the plum stone. Untill they are chopped up we can't get to quality fermentation.

So the mixing and choppng them all up serves to chop up the fruit 'meat' in such a way that it is seperated from the plum stones most of which drift down to the bottom of the barrel...





Mixing the plums completed

If you scroll up a couple of images where we were topping up the barrel with the last harvest of plums, compared to this image you'll notice that the level of the brew content has gone down a bit.

This is due to the mixer which in chopping up the plums has shreded everything and hence more space has been attained inside the barrel


and the plums let out their juices and this is why level has gone down


... and this is how it should be as the fermenting process is 2 thirds way through and by now if there were no smell of alcohol near our barrel Luda would be worried it would mean that the fermantion is not of right quality


Final fermenting brew

And here we have the brew after the mixing has been completed.

When smelling-active-internet-protocoll has been invented I'm sure you will enjoy the alcohol-like aromatic fumes of thie slivovitz fermentation which at this point emmanate from the barrel but for now here is a descriprion.

The aroma around the barrel smells like a whiff of Slivovitz, between fermenting fruit and alcohol leftovers after a party...




... waiting 4 to 6 weeks, no more mixing, the fermantation is not moved, and the top is smooth to get a crust on top, which servers to seal the lower fermantation liquid.


Last stage of fermenting the chopped up plums before distilling

The last stage consist of putting the lid onto the barrel and then just waiting....




Last but not least - the wood needed for distilling Slivovitz.


This isa pile of wood in Luda's garden for the sole purpose of being taken along to the distillery when we then go there.

The boilers at the Slivovitz distillery are heated by wood stoked fires.

As the year 2005 was a poor plum harvest year, only about a quarter of this pile of wood will be necessary.

See next section for the rest on stoking the Slivovitz boilers.

So how do we know when to stop fermenting the plums ?



How do we know when the
fermentation process of the plums has completed ?

How do we know how not to over ferment or under ferment our plum brew ?

Ahhhh..... this is the real secret of the professional Slivovitz maker and you have to pay us 200 dollars via credit card to find out.

... just kidding.

In a nutshell this is very simple and although is minimally based upon experience, Luda tells me that having gotten to this stage where all the plums have been chopped up, all that has to be done is to check out the brew once a week, or twice a week if the weather is warmer than usual to see the 'bubbling' and lifting rising, This is also why a fermenting container should not be filled to the brim and as you saw - in our case about 20 cm of headroom were left so that our precious soon to be Slivovitz would not overflow whils the plums were fermenting.
After the chopping up of the plums the level goes back down a bit.

Whilst fermenting and towards the end of this phase the whole brew sends up bubbly foam to the top.
You can see these fermantation bubbles pop up just by watching for 1 or 2 minutes.

So when the day arrives where you have been staring at the brew for 5 minutes and have seen very few bubble motions occur - now is the time to go to the distillery.
The fermantation is ready for distilling.

Also by now the crust on top of the brew should have formed and this then serves as an almost airtight natural lid for what is beneath it.

The 'experience' part in all of this just comes in when the weather changes and if each end of summer - start autumn had exactly the same weather conditions you would not need any experience at all.
So with his experience, Luda knows that if October is unusually warmer then the fermentation will be faster.

Even if this happens - that the outside temperature is hot, Luda avoids moving the fermentation barrel inside, say a garage, cellar or a shed so as not to get bad and stuffy air back into the frmentation brew.
This has to be kept in fresh air, even if it warms up.

Being the Czech Republic, in the 30 years Luda has been making Slivovitz it has never happened that the autumn were so hot to worry and in any case, even if the weather does get too hot, after fermantation is completed, the crust layer keeps the all the fermented brew bottled down.

After fermantation one could theoretically leave it there for another 3 months - what is not exactly correct, and could worsen the quality of fermantation.

And if October and November turn out to be exceptionally colder, than the timeline for fermantation is prolonged untill the bubbling has stopped.

Continue now to the next section which is the actual distilling of the fermented plum brew into top class distilled Slivovitz.


A short recap of what has been done up til now on our way to obtaining top class Slivovitz:

Plums have been harvested, (or you can allways buy them in bulk if you don't have any plumtrees yourself.

From the first plum picking to the last, the plums have beed placed and added into our fermenting container, with the lid placed on it.

After about a month from the initial first load of plums that was placed into the container, and probably a few days after the last load of harvested plums were added, and by now the whole bre has a nice alcoholic fruity smell, the whole brew is chopped up with our plum chopper mixer.

Now the whole chopped up brew is left for 4 to 6 weeks, or untill the fermenting bubbles stop coming up, the surface has settled and a crust has formed.

From this moment in the process we can distill our fermented plums whenever we like and a suggested period within which to do this after the fermantation has stopped would be anything from then on up to 2 to 3 weeks.
If weather is very hot after the end of fermantation - the distilling should be done sooner than later.