Other Fermentation temperature for kit wines from juice

Winemaking Talk - Winemaking Forum

Help Support Winemaking Talk - Winemaking Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Gareth d

Jan 25, 2024
Reaction score
I was wondering what other people's thoughts are on fermentation of kit wines from juice.

I have made a few kit wines with great success, but I don't own a heater and usually ferment in the summer when the room temperature is warmer.

As you may be able to tell, I have a red kit that is asking to be started.

Clearly it is necessary to have enough warmth to prevent a stuck fermentation. But most sources seem to suggest warm is better for fermentation of reds to help extract tannins from the skins, usually at least 20, and perhaps even more than 25 degrees.

I am wondering whether if the temperature that a kit instruction states is all that relevant for a wine that doesn't have skins - I presume any tannin has probably been added to the juice bag already. In which case , other than speed and risk of a stuck fermentation would it make much difference to the taste if the temperature was slightly below 20, or even in the high teens?
In the fall I ferment my wines at cellar temperature, which ranges from 63 F / 17 C to 68 F / 20 C, and I have no problems with fermentation. I've fermented white kits at 58 F / 14.5 C and while the ferment took 5 weeks, it completed fine.

Others report that they ferment at their ambient cellar temperature with no problems.

In the past few years I've been making overnight starters, which enable the yeast to grow into a larger initial colony, so I get a relatively quick fermentation even at cold temperatures.

Colder ferments are supposed to preserve aromatics which can be blown off by a hotter ferment, while hotter ferments for reds extract more color and tannin from the skin, pulp, and seeds. For red juice or concentrate? It doesn't appear that a hotter ferment will produce better results in this area.
If you have no skins in your kit I think temperature matters less in terms of extraction. I think that the yeast starter idea is a good one, as is yeast nutrition (if you are worried about a stalled/stuck ferment), and yeast selection. You can always use something like champagne yeast (which many kits come with - EC-1118) as that never gets stuck nor does it need nutrients. Perhaps even starting with the yeast of your choice, then adding the EC-1118 towards the end of the ferment. Some higher end kits even include two yeasts for this reason (but don't add the EC-1118 at the beginning as it is a 'killer yeast' which will dominate the party from the start, out competing the other yeast).

An interesting thing about temperature is how much an active ferment will increase the temperature internally. However, if you only have a 6 gallon ferment in a bucket, there is a ton of exposure to your room temperature. So you could wrap your fermenter with blankets or jackets which will allow that internally generated heat to stay inside. I sometimes ferment in Igloo or Gott coolers for this reason, it really keeps the heat in a smaller volume ferment.
Thanks both , that was my feeling.

It is a good idea the yeast starter - I have done that a few times with live yeast packs for beer but hadn't occured to me this time.

Quite right the kit comes with the ec-1118 yeast so it the room temperature (around 17 deg) is well within range for fermenting.

I will get cracking on this one - it is an older discounted winexpert LE22 (cab sauvignon /merlot).

Here is another perspective from a rookie: I just started my first kit last week, and I ran into the same issue; cold cellar temp which peaked around 68F (20C) when I turned the heat up in my house. Fermenting upstairs was a no-go with my spouse, so I self engineered a reliable adjustable space heater about 3ft away from my primary bucket which I put inside a box tipped up on its side as a sort of backstop for the warm air.

With that I was able to maintain a 78-80F (26C) ambient temp directly around the Fermentation bucket. the EC-1118 kicked off within 16hrs and I capped my bucket last night when the SG hit 1.012. So it has been rather successful -- the must temperature peaked at 79F at 1.030 before the fermentation started to slow.

Latest posts