Spongey Layer on top of Cider? (krausen?)

[BaronBooty]

Hello! Sort of in a panic situation, as I am pretty new to homebrewing, and tried my first cider with puree in it.

I put in about 4 gallons of store-purchased cider, and added about 3lbs of blueberry puree, with LALVIN EC-1118 as yeast, as well as basic nutrient added in at the beginning.

After about a week, I was expecting to bottle, and saw this:

From what I have read online, it SOUNDS like "krausen", but given the purple color due to the blueberries, and my complete inexperience, I wanted to ask more experienced homebrewers! I shut the lid back on with the airlock, and here I am. It is very spongey to touch, so I am very nervous about it. There are white little specks on top as well, but I am unsure if that is normal.

If it IS krausen, I have a few questions:
- Is it still safe?
- What should I do now? Should I let it keep fermenting? Should I bottle around it?

Thank you very much!

 

[ShadesManna]

For those of you like me, who don't know what krausen is, here's an answer courtesy of DuckDuckGo:

The term Krausen is derived from a German word for ‘curly’. It describes the foamy build up on the surface of beer that occurs in fermentation caused by yeast. Krausen can be a good indicator of both the start & end of fermentation. This should be confirmed by measuring the wort’s Specific Gravity.

In traditional wine making, this is usually called the cap. It's basically when all of the mashed up grapes, skins, etc. float to the top of the must during fermentation. Winemakers punch it down, breaking it up during the primary fermentation, to help make sure everything goes smoothly.

It sounds and looks like you might have a "cap" of blueberry puree. The cracks and holes in it are good indications that fermentation is still going on below the surface. Another way to know this is to check if your airlock is still bubbling away. You can choose to punch it down, like winemakers do, or you can leave it alone. Punching it down might help mix everything together, and make sure all those blueberries are adding their flavors to the must. Also, if you choose to punch it down, you can literally take a peek at the liquid underneath, and see how things are going. It will merely take a little longer to clear.

 

[BaronBooty]

That is absolutely fascinating! I looked up wine cap, and it does look very similar - do you think it would be an issue that I haven't been punching it down over the past week? I read that traditional winemakers punch down multiple times per day. And would the tiny white specks on top of the cap be an issue?

What an interesting plot twist

 

[Yooper]

Yes, it's definitely a cap. I'd stir- any cap like can get some mold if exposed for a long time like that. Use a sanitized dowel or long spoon, and gently stir. My guess is that it's nearly done, so you don't want to oxidize it, but I can't tell just from looking of course. Take an SG reading after you stir, to see where you're at- but you're definitely NOT ready to bottle!

 

[BaronBooty]

Fantastic - thank you both SO much. You turned a stressful morning into a considerably better situation.

I went ahead and stirred in the cap, and will let it do its thing until it is done!

 

[Chalkyt]

EC1118 is a fairly aggressive yeast and might "blow off" some of the flavour, so punching down shouldn't hurt. My go-to yeast is SO4 (if I can't get WLP775) which also quite quick acting and produces a thick primary "foam" which settles after a week or so. Jolicoeur calls this the "turbulent" primary phase and when it settles (usually around SG 1.030) it is a good time to transfer to secondary. I agree with the above responses... you simply developed a turbulent foam or cap. I look for this to happen as it indicates a good robust ferment.