Cause of light brown grainy layer at bottom of yogurt?
Hi Everyone,
Recently, we are getting issue with the yogurt. Light brown grainy layer, some kind of sediment is seen at bottom of the yogurt. To brief the process, we started using skim milk to standardized the whole milk, so in turn to increase the total solid content we increased the qty of skim milk powder & also we are homogenizing after adding skim milk powder to the milk. I guess this might be due to improper hydration. I don't understand where I am processing wrong. Any help will be appreciated.
Thank you.
Poonam
Hello
Colour change as "light brown" can appear from ingredient or process.
Process:
What's hydration time and temperature? Should be around 40Deg for 20 min (agitated).
Is your pasteuriser free of build-ups? Can be some burnt product if you don't conduct inspection regular. What is your flow rate on the pasteurser? I should be around 5,000 L/hr (depends on the pipework). If it's too slow cam be burnt. product. Usually if we have flow rate going down then it's a burning sign.
Do you have any other products that have brown component? Can be cacao powders from other recipes. Then it's a cascading process to be improved.
Is the layer consistent or lumpy? What's your protein level in the recipe? Is it a pot set or stirred yoghurt?
Do you have photos?
Cheers Marina.
Hi Everyone,
Recently, we are getting issue with the yogurt. Light brown grainy layer, some kind of sediment is seen at bottom of the yogurt. To brief the process, we started using skim milk to standardized the whole milk, so in turn to increase the total solid content we increased the qty of skim milk powder & also we are homogenizing after adding skim milk powder to the milk. I guess this might be due to improper hydration. I don't understand where I am processing wrong. Any help will be appreciated.
Thank you.
Poonam
Rusty equipment ?
Rusty equipment ?
No Charles, Our equipment is new. and we are maintaining good
Hello
Colour change as "light brown" can appear from ingredient or process.
Process:
What's hydration time and temperature? Should be around 40Deg for 20 min (agitated).
Is your pasteuriser free of build-ups? Can be some burnt product if you don't conduct inspection regular. What is your flow rate on the pasteurser? I should be around 5,000 L/hr (depends on the pipework). If it's too slow cam be burnt. product. Usually if we have flow rate going down then it's a burning sign.
Do you have any other products that have brown component? Can be cacao powders from other recipes. Then it's a cascading process to be improved.
Is the layer consistent or lumpy? What's your protein level in the recipe? Is it a pot set or stirred yoghurt?
Do you have photos?
Cheers Marina.
Hi Marina
Thank you for your time. Hydration time is 20 min at 48 Deg.C . We use batch pasteurizer and is maintained good. After the hydration process milk is sent to the homogenization and followed by pasteurization. Its plain yogurt ingredients mainly are milk, Skim milk powder & stabilizer.its set yogurt. Total solid content is 13.5%. Please see attached photos for reference its before incubating yogurt.
Thank you very much.
Poonam
Attached Files
Scorched powder. Do you check the scorch level of your incoming skim powder? I would...don't trust the COA's. I've seen this too many times to count.
It could also be lactose settling out, but I bet money it is scorched milk powder particles.
Completely agree with Ryan M.: scorched SMP. We're yogurt manufacturer as well, and I don't recall we've had this problem. Though, our yogurts're natural - meaning, we don't add stabilizers. Check also stabilizer: what's in it? Interesting, that brown substance is forming at the bottom: so, when you fill up your cups, some particles (not homogenized) gravitate to the bottom forming that layer...
Thank you everyone for your time and the contribution. I investigated the issue, the issue was with the process. when we mix the Skim Milk Powder at 40 deg Cel it forms a foam, mixing is done directly in the batch pasteurizer, the wall of the pasteurizer is hot so the particles in foam gets burned and sediments. So we are now mixing at lower temperature with continuous agitation and hydrating for 20 min. Now we are not getting brown layer at bottom.
Thank you again.
Poonam
Good news, but to me, that temperature is not hot enough to burn or scorch the particles. It is actually a good temperature to mix the SMP. Just be wary because I think you may have another issue that's leading to the brown, grainy layer.
Thank you everyone for your time and the contribution. I investigated the issue, the issue was with the process. when we mix the Skim Milk Powder at 40 deg Cel it forms a foam, mixing is done directly in the batch pasteurizer, the wall of the pasteurizer is hot so the particles in foam gets burned and sediments. So we are now mixing at lower temperature with continuous agitation and hydrating for 20 min. Now we are not getting brown layer at bottom.
Thank you again.
Poonam
Makes sense that the SMP will reduce foam at lower temp like 20Deg (we had the same issue at batching stage when the foam was overflowing) and get burnt during pasteurisation. Good learning curve.