how do you use videne

[tubthumper]

I finally got some videne antiseptic solution today and need to find out the required strengths i need for a no rinse steriliser for both my corneys and bottles
anyone able to offer any advice please

 

[jamesb]

Use 1.25ml of Videne per 1l of water for a no-rinse solution.

You don't need to fill the cornies up, just fog the insides, or use a litre and swish it around. As long as the surfaces are wetted it'll be fine.

 

[Vossy1]

For interest, and in case you don't know, you can also use Videne to check your mash is fully converted.
Simply put a drop of videne on a white plate and add some of the runnings from your mash.
If it stays brown conversion in the mash is complete.
If it turns purple let the mash 'mash' for longer and retest until the test stays brown :thumb:

The purple colour indicates there is still starch in your mash and that it hasn't been converted to sugar yet.

 

[Muddydisco]

Great tip that V, I'd forgot that iodene reacts with starches :thumb:
Next mash I shall have a new photo to post

 

[tubthumper]

Thanks guys
will do that come botteling time and next mash will use the vossy tip

 

[Aleman]

For interest, and in case you don't know, you can also use Videne to check your mash is fully converted.
Simply put a drop of videne on a white plate and add some of the runnings from your mash.
If it stays brown conversion in the mash is complete.
If it turns purple let the mash 'mash' for longer and retest until the test stays brown :thumb:

The purple colour indicates there is still starch in your mash and that it hasn't been converted to sugar yet.

There was a good article in one of the recent Brewers Contacts that described the 'proper' way to do an Iodine test . . . and just what all the colours mean. . . . . I'll ask the author if he minds it being posted here :whistle:

 

[Vossy1]

:lol:
Go on then, as long as it's not too scary :grin:

 

[Aleman]

:lol:
Go on then, as long as it's not too scary :grin:

When using modern malts is there any point in checking for conversion using iodine solution? Many brewers will say not, as most modern malts are so consistent they are ‘certain’ to convert all of the starch to sugar. In the vast majority of cases they would be right, however, properly conducted, an iodine test tells a brewer so much more than ‘the starch has been converted’.

At a pinch a dilute (12.5ppm) solution of iodophor can be used, but more consistent results can be obtained using a 0.02N solution of iodine (1.27g Iodine, 2.5g Potassium iodide in 500ml of distilled water). Place a sample of the mash liquid (ideally free of solids, as they will always turn blue black), in a white porcelain dish, then float several drops of iodine onto the extract, until a distinct layer is formed. Note any colour change in the iodine at its interface with the mash liquid. Also observe the intensity of the colour; is it trace, faint or strong?

The presence of starch is indicated by a blue-black colour and is fairly unmistakeable, gelatinised starch (amylose fragments, and large a-limit dextrins) produces a deep mahogany red brown colour. If the colour change is a faint red this indicates the presence of simple a-limit dextrins, a faint mahogany to violet reddish this shows the existence of small dextrins. Total mash saccharification (small a-limit dextrins with maltotriose, maltose and simple sugars) cause no change in the yellow colour of the iodine

Most of the starch should be reduced to at least small a-limit dextrins by alpha amylase. Even for sweet less fermented beers, the reaction should be no more than faintly mahogany to red. There should never be a strong colour reaction with the iodine; neither however, should rich beers be saccharified to the point that a negative iodine reaction occurs. A faint mahogany to reddish reaction indicates an acceptable extract composition for these beers.