I would stem them. The stems do affect the flavor.

You can process the grape juice directly after but sediment, especially tartaric acid crystals, will form in the bottom of the jar. It won't do any harm; it just makes the juice less appealing.

Otherwise, the usual procedure is to strain the juice, refrigerate from 24-48 hours, pour off the juice above the sediment. At that point you can either strain again (I do for grape jelly) or you can follow the usual process and can.

So you have 3 choices: 1) No straining at all 2) Strain, let sit 24-48 hours and can or 3) Strain, let sit, strain again and can.

It depends on how much you're bothered by a muddy-looking layer and crystals at the bottom of the jar. It bugs some, doesn't make a bit of difference to others.

Processing time's at the link. It's pretty short.

Carol

Here is a link that might be useful: How to Can Grape Juice

Thanks Carol. I may do a batch each way and see which we prefer. I have rows and rows of grapes so no worries there! A friend and I may try our hand at making wine too. Should be fun!

I'd found that link but wasn't sure if the processing would be different since I'm doing concentrated juice and not adding water or sugar. Thanks!

Lora

Sorry, I missed that issue. Grapes are high-acid and many grapes are very high-acid, so there's no concern.

The water they direct be added is principally to cook the grapes without scorching. Since you're using a steamer, there will be some moisture, but less. That's OK. The sugar is irrelevant. It doesn't affect pH and is added only according to personal preference or can be left out entirely.

Carol

The VIllaware food strainer also can handle grapes, provided you have the shorter grape spiral and also use the berry screen, or tomato screen. This process doesn't use any water to assist the juice extraction.

I love my steam juicer ! This is the 3rd one I have gotten so far. The first was aluminum, and it was free. Then, the second was blue enamel. Now I gave the blue one to a friend and got a stainless one. I have been using it quite a bit. I did grapes. I do like taking them off the stems, to. I let my juice sit in the fridge overnight because I don't want the sediment or tartaric crystals in mine.
I freeze my juice, not can it since I am just taking it out for jelly. Don't want to use up lids to can it and take the time or use the gas stove to do it.
Such rich, strong juice I get from the steam juicer. Really wonderful flavor.

I have a food strainer too and will probably try that. I have the shorter spiral for grapes but last time I tried it they still clogged. I'll give it another shot with the wine grapes. That'd be a great way to get pulp for jam!

When you let it sit in the fridge for 24 do you then reheat it and can hot or can you pour it cold, put jars in canner, then turn on the heat? Is one way better?

Thanks again!
Lora

You have to reheat and put in the jars hot (which means the jars have to be warm, also, not cold).

Also, assuming you're doing pints or quarts, you can either sterilize jars and process the 5 minute time or just use hot clean jars and process 10 minutes instead (like jam).

Carol