Loganberries and Pot Met

[TStarr]

Hi all, grateful if someone could clue me in as to what's going on here - I picked a load of Loganberries, which unfortunately. got washed and put in the fridge, not the freezer - day or so later, I found them, threw away some iffy soggy looking examples, gave them a quick whisk in a blender, then, in an attempt to kill any nasties, added a "1 gall" measure of Pot Met and returned them to the fridge whilst deciding on their fate.

Looked at them 12 hrs later, and the mix had gone a light pink, creamy colour - if I had juiced the loganberries, and added Pot Met, as in 24 hrs before adding yeast, I would not have expected the must to change colour like this - so does anyone have any idea what might have happened?

[Cellar_Rat]

Pot met does have a bleaching effect.. did you have a gallon of berries?

[Cellar_Rat]

How much did you add and was it potassium or sodium?

[TStarr]

Probably only around 2 pints of Loganberry tbh, and just 1 of the tiny measuring spoons, which I am pretty sure are for 1 gallon of must. I was trying to err on the safe /killing side, assuming if I heated the mixture later it would drive any chemicals off.

I used Potassium rather than Sodium. Would either have done the same?

Is this a daft way of trying to even temporarily preserve fruit (the freezer is full of last years harvest .... don't ask) or prevent spoilage for a few days?

[fatbloke]

Its about raising sulphur content to about 50ppm or so.

1 campden tablet provides 44 ppm in 1 imp gallon or 50 ppm in 1 US gallon.

If the measuring spoon is for measuring the amount for 1 gallon, then its quite feasible that you effectively gave it a double dose so its quite possible that there might have been some bleaching effect as Brian points out.

Plus heating the fruit material can cause issues with pectins later on.....

[Cellar_Rat]

Sodium and potassium are very similar but potassium is said to be stronger (& more expensive).
Commercial wineries only use sodium metabisulphite washing stuff in.

If you are talking about a domestic set of measuring spoons the smallest one is 2.5 ml.

If this is potassium metabisulphite powder (aka KADIFIT) they have had a massive dose. I use 8 g of powder (which is pretty much 8 pinches) for 50 gallons. that will be why they have bleached. I'm surprised you couldn't smell the sulphur when it hit the juice.

[lockwood1956]

Other way round....

Sodium metabisulphite is around 8-13% stronger

They have had a very large dose of sulphite, (1/4 teaspoon being enough for a 5 gallon batch) but I wouldnt worry too much about it as the flavour shouldnt have been compromised!

just be careful layter when making wine that you dont add any more sulphite (if making a gallon)

I find it better to make a sulphite solution and add this, I find it a much more accurate measure (5ml per gallon)

I dont like to use a blender with berries containing seeds as smashing the seeds can add bitterness to the finished wine



hope that helps
regards
bob

[oliver90owner]

The change in colour could simply be a change in pH. Many natural colourings can be used as indicators of pH. Could also be a chemical change due to the SO2.

For instance my rhubarb juice was pink but changed to colourless on addition of a good dose of metabisulphite; pinkness (or some of it) returned when I fermented it.

Potassium has a higher atomic mass than Sodium. Not so far off twice, so the K-metabisulphite will have less sulphur dioxide per unit weight for that reason. I need not go into molecular mases of the two compounds, but the effectiveness is governed by that and also the slightly different reactions of the two elements (although they are very similar - both group I elements and only one row apart in the Periodic Table).

RAB

[Cellar_Rat]

Other way round....

Sodium metabisulphite is around 8-13% stronger

Yes indeed - my fingers just can't be trusted to type what I ask them !!

[koomber]

Red wine is a good indicator of pH. If you've ever used a caustic cleaner on your brew stuff, you'll notice the remains go a funky blue colour.

[Cellar_Rat]

I use truck wash on everything - partly because it gets the red wine stain off so well.

So the funky blue colour is a PH swing then. Makes sense when you think about it, but I never had before. thanks.